02 Chep Thermodynamics and Thermochemisty Ques. Final E

8/18/2019 02 Chep Thermodynamics and Thermochemisty Ques. Final E

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158 Thermodynamics and Thermochemistry

9. Heat produced in calories by the combustion of

one gram of carbon is called

(a) Heat of combustion of carbon

(b) Heat of formation of carbon

(c) Caloric value of carbon(d) Heat of production of carbon

10. Conditions of standard state used in

thermochemistry is

(a) Co0 and 1 atm (b) Co20 and 1 atm

(c) Co25 and 1 atm (d) K 0 and 1 atm

11. The temperature of the system decreases in an

(a) diabatic compression (b) !sothermal

compression

(c) !sothermal e"pansion(d) diabatic e"pansion

12. #or the isothermal e"pansion of an ideal gas

(a) $ and H increases(b) $ increases but H decreases

(c) H increases but $ decreases

(d) $ and H are unaltered

13. !f a refrigerator%s door is opened& then 'e get

(a) oom heated

(b) oom cooled

(c) ore amount of heat is passed out

(d) *o e+ect on room

14. The cooling in refrigerator is due to

(a) eaction of the refrigerator gas(b) $"pansion of ice

(c) The e"pansion of the gas in the refrigerator

(d) The 'or, of the compressor

15. -oint out the 'rong statement in relation to

enthalpy

(a) !t is a state function

(b) !t is an intensive property

(c) !t is independent of the path follo'ed for the

change

(d) !ts value depends upon the amount of

substance in the system

16. .hich of the follo'ing is /ero for an isochoricprocess

(a) dP (b) dV

(c) dT (d) dE

17. ar, the correct statement

(a) #or a chemical reaction to be feasible& G∆should be /ero

(b) $ntropy is a measure of order in a system

(c) #or a chemical reaction to be feasible& G∆should be positive

(d) The total energy of an isolated system is

constant

18. !n an isochoric process the increase in internal

energy is

(a) $ual to the heat absorbed

(b) $ual to the heat evolved

(c) $ual to the 'or, done

(d) $ual to the sum of the heat absorbed and'or, done

19. !t is general principle that the less energy a

system contains& it is

(a) ess stable (b) ore stable

(c) nstable (d) ore unstable

20. !nternal energy is an e"ample of

(a) -ath function (b) 3tate function

(c) 4oth (a) and (b) (d) *one of these

21. The process& in 'hich no heat enters or leaves the

system& is termed as

(a) !sochoric (b) !sobaric

(c) !sothermal (d) diabatic

22. The intensive property among these uantities is

(a) $nthalpy (b) assvolume

(c) ass (d) 6olume

23. !n thermodynamics 'hich one of the follo'ing is

not an intensive property

(a) -ressure (b) 7ensity

(c) 6olume (d) Temperature

24. !f in a container neither mass and nor heat

e"change occurs then it constitutes a

(a) Closed system (b) 8pen system

(c) !solated system (d) !maginary system

25. .hich of the follo'ing is not a state function

(a) S∆ (b) G∆(c) H∆ (d) Q∆

26. .hich of the follo'ing is true for an adiabatic

process

(a) 0=∆H (b) 0=∆W

(c) 0=∆Q (d) 0=∆V 27. .hich of the follo'ing is not a state function

(a) !nternal energy (b) $nthalpy

(c) .or, (d) $ntropy

28. mong them intensive property is

(a) ass (b) 6olume

(c) 3urface tension (d) $nthalpy

First law of thermodynamics and Hess law

1. The rst la' of thermodynamics is only

(a) The la' of conservation of energy

(b) The la' of conservation of mass

(c) The la' of conservation of momentum

(d) 4oth (a) and (b)

2. mi"ture of t'o moles of carbon mono"ide and

one mole of o"ygen& in a closed vessel is ignited to

convert the carbon mono"ide to carbon dio"ide9 !f

H∆ is the enthalpy change and E∆ is thechange in internal energy& then


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(a) EH ∆>∆

(b) EH ∆


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Thermodynamics and Thermochemistry 160

(b) 2log;0;92;19D102ED F ×××

(c) 590log0D2902ED;0;92 ××

(d) 590log;0;922ED10;19D F −××

(e) 2log22ED;0;92 ××

19. The la' of conservation of energy states that

(a) The internal energy of a system is constant

(b) The heat content of a system is constant

(c) $nergy is neither created nor destroyed

(d) There is an euivalence bet'een energy and

mass

20. The enthalpies of the elements in their standard

states are assumed to be

(a) ero at 2ED G

(b) nit at 2ED G

(c) ero at all temperatures

(d) ero at 2F; G

21. The heat Q for a reaction at constant volume is

eual to

(a) RP HH − (b) PR HH −

(c) RP EE − (d) *one of these

22. .hich of the follo'ing e"pressions represents the

rst la' of thermodynamics

(a) W qE +−=∆ (b) W qE −=∆

(c) W qE +=∆ (d) W qE −−=∆

23. !n a reversible isothermal process& the change in

internal energy is(a) ero (b) -ositive

(c) *egative (d) *one of these

24. schematic plot of eqK ln versus inverse of

temperature for a reaction is sho'n belo'

The reaction must be

(a) $"othermic

(b) $ndothermic

(c) 8ne 'ith negligible enthalpy change

(d) Highly spontaneous at ordinary temperature

25. Hess la' of heat summation includes

(a) !nitial reactants only

(b) !nitial reactants and nal products

(c) #inal products only

(d) !ntermediates only

26. n ideal gas at constant temperature and pressure

e"pands& then its(a) !nternal energy remains same

(b) !nternal energy decreases

(c) !nternal energy increases

(d) $ntropy rst increases and then decreases

27. The internal energy of a substance

(a) !ncreases 'ith increase in temperature

(b) 7ecreases 'ith increase in temperature

(c) Can be calculated by the relation 2mcE =(d) emains una+ected 'ith change in

temperature

28. The relation bet'een change in internal energy

)( E∆ & change in enthalpy )( H∆ and 'or,

done (W ) is represented as

(a) W EH +∆=∆ (b) HEW ∆−∆=

(c) HW E ∆−=∆ (d) W HE +∆=∆29. The enthalpy of neutrali/ation of 'hich of the

follo'ing acids and bases is nearly KcalH91;−

(a) HCN and NaOH (b) HCl and KOH

(c) HCl and NaOH (d) HCl and NHIOH

30. .or, done during isothermal e"pansion of one

mole of an ideal gas from 10 atm to 1 atm at ;00

K is (Jas constant K 2)

(a) E;D9D cal9 (b) 11;D9D cal9

(c) 1;D19D cal9 (d) 15D19D cal.

31. @ouleLThomson e"pansion is

(a) !sobaric (b) !soenthalpic

(c) !sothermal (d) *one of these

32. !n 'hich of the follo'ing HE ∆=∆

(a) )(I2 gON < )(2 2 gNO(b) )()(2 22 gOgSO + < )(2 ; gSO

(c) )()( 22 gIgH + < )(2 gHI

(d) )(2

1)( 22 gOgH +


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(a) a' of conservation of mass

(b) a' of conservation of energy

(c) $nthalpy is a state function

(d) *one of these

37. #or the reaction&

)(I)(;)(5)( 222D; lOHgCOgOgHC +→+

at constant temperature& EH ∆−∆ is

(a) A RT (b) N RT

(c) A ;RT (d) N ;RT

38. ccording to HessPs la'& the heat of reaction

depends upon

(a) !nitial condition of reactants

(b) !nitial and nal conditions of reactants

(c) !ntermediate path of the reaction

(d) $nd conditions of reactants

39. The value of EH ∆−∆ for the follo'ing reactionat Co2F 'ill be )(;)()(2 22; gHgNgNH +→

(a) )2(2F;;1I9D −×× (b)

)2(;00;1I9D −××

(c) )2(2F;1I9D −×× (d) )2(;00;1I9D ××

40. #or 'hich of the follo'ing HE ∆=∆

(a) )(I2 gON < )(2 2 gNO

(b) )()(2 22 gOgSO + < )(2 ; gSO

(c) )()( 22 gClgH + < )(2 gHCl

(d) )(2

1)( 22 gOgH + < )(2 lOH

41. 8ne mole of an ideal gas is allo'ed to e"pand

freely and adiabatically into vacuum until its

volume has doubled9 statement 'hich is not true

concerning this e"pression is

(a) 0=∆H (b) 0=∆S

(c) 0=∆E (d) 0=W

42. t &2F Co one mole of an ideal gas is

compressed isothermally and reversibly from a

pressure of 2 atm to 10 atm9 The values of E∆and q are )2( =R

(a) 0& A E59DI cal

(b) A E59DI cal& N E59DI cal

(c) N D595D cal, A D595D cal

(d) A D595D cal, A D595D cal

43. The 'or, done by a system is D #o$le, 'hen I0

#o$le heat is supplied to it9 .hat is the increase in

internal energy of system

(a) 25 ! (b) ;0 !

(c) ;2 ! (d) 2D !

44. system absorb 00 ! of heat and 'or, euivalent

to ;00 ! on its surroundings9 The change in internal

energy is

(a);00 ! (b) I00 !

(c) 500 ! (d) 00 !

45. .or, done during isothermal e"pansion of onemole of an ideal gas from 10 atom9 to 1 atm at

;00G is

(a) IE;D9D ! (b) I1;D9D !

(c) 5FII91 ! (d) 25F92 !

46. !f gas& at constant temperature and pressure

e"pands then its

(a) $ntropy increases and then decreases

(b) !nternal energy increases

(c) !nternal energy remains the same

(d) !nternal energy decreases

47. #or the reaction

)()()( 2;5 gClgPClgPCl +→

(a) EH ∆=∆ (b) EH ∆>∆

(c) EH ∆

(c) 0= (d) oE∆<

50. 8ne mole of an ideal gas is allo'ed to e"pand

reversibly and adibatically from a temperature of

Co2F 9 !f the 'or, done during the process is

!; & then nal temperature of the gas is

)20( K !CV =

(a) 100 K (b) 150 K

(c) 1E5 K (d) 255 K

51. .hich of the follo'ing is correct regarding theinternal energy of a substance

(a) !t is a state function

(b) !t increases 'ith increase in temperature

(c) !t can be calculated by e"periment

(d) !t remains una+ected 'ith change in

temperature

52. #or the gaseous reaction&

2I2 2NOON →

(a) EH ∆∆


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53. !HCOOC 220=22 2 −=∆→+

.hich of the follo'ing statement is correct for this

reaction

(a) Heat of combustion of carbon is 110 !

(b) eaction is e"othermic(c) eaction needs no initiation

(d) ll of these are correct

54. n ideal gas e"pands in volume from ;;101 m−×

to ;2101 m−× at ;00 K against a constant

pressure of 25101 −× Nm 9 The 'or, done is

(a) 2F0 ! (b) AE00 !

(c) AE00 ! (d) E00 !

55. !nternal energy is

(a) -artly potential and partly ,inetic

(b) Totally ,inetic

(c) Totally potential

(d) *one of these

56. #or 'hich of the reaction EH ∆=∆

(a) 22 ;HN + < ;2NH (b) NOON 222 →+

(c) NaClClNa 22 2 →+ (d)

2;5 ClPClPCl +→

57. The 'or, done during the e"pansion of a gas from

a volume of ;Idm to ;Hdm against a constant

e"ternal pressure of at ; is ( !atm& ;291011 = )

(a) N ;0I ! (b) A;0I !

(c) A ! (d) A0D !

58. #or the reaction& )()()()( I2 l'g' (C) * +→+ 9

H∆ and U∆ are related as MMM

(a) UH ∆=∆ (b) RT UH ;+∆=∆

(c) RT UH +∆=∆ (d) RT UH ;−∆=∆

IInd & IIIrd Law of thermodynamics and Entropy

1. #or a reversible spontaneous change S∆ is

(a)T E∆ (b)

T V P ∆

(c)T

q (d) RT log K

2. .hen disorder of a system increases& the changeis said to be

(a) $"othermic (b) *onLspontaneous

(c) $ndothermic (d) 3pontaneous

3. The spontaneous Qo' of heat is al'ays

(a) #rom lo' to high pressure

(b) #rom high to high pressure

(c) nidirectional from lo'er temperature to

higher temperature

(d) nidirectional from the higher to lo'ertemperature

4. i"ing of nonLreacting gases is generallyaccompanied by

(a) 7ecrease in entropy

(b) !ncrease in entropy

(c) Change in enthalpy

(d) Change in free energy

5. n irreversible process occuring isothermally in anisolated system leads to

(a) ero entropy

(b) n increase in the total entropy of the system

(c) decrease in the total entropy of the system

(d) *one of these

6. The entropy values (in !K L1 molL1) of H2(g) K 1;09&Cl2(g) K 22;90 and HCl(g) K 1D9F at 2ED K and 1atm pressure9 Then entropy change for thereaction

)()(2)(2 2 ggg HClClH →+ is

(a) N 5I09; (b) N F2F9;

(c) A 19E (d) N 1E9D

7. .hich of the follo'ing is the least random state of 'ater

(a) !ce

(b) iuid 'ater

(c) 3team

(d) ll present same random state

8. .hich one of the follo'ing process is nonLspontaneous

(a) 7issolution of IC$SO in 'ater(b) eaction bet'een 2H and 2O to form 'ater

(c) .ater Qo'ing do'n hill

(d) #lo' of electric current from lo' potential tohigh potential

9. .hich of the follo'ing is /ero during adiabatice"pansion of the gas

(a) T ∆ (b) S∆

(c) E∆ (d) *one of these10. The entropy of crystalline substances at absolute

/ero going by the third la' of thermodynamicsshould be ta,en as

(a) 100

(b) 50

(c) ero

(d) 7i+erent for di+erent substances

11. !n 'hich state& the matter have highest entropy

(a) 3olid (b) iuid

(c) Jas (d) $ual in all

12. .hich of the follo'ing pairs of a chemical reactionis certain to result in spontaneous reaction :

(a) $"othermic and decreasing disorder

(b) $ndothermic and increasing disorder

(c) $"othermic and increasing disorder

(d) $ndothermic and decreasing disorder


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163 Thermodynamics and Thermochemistry13. .hen one mole of monoatomic ideal gas at T K

undergoes adiabatic change under a constante"ternal pressure of 1 atm changes volume from 1litre to 2 litre9

The nal temperature in Gelvin 'ould be

(a) );52(2

T (b) T N

0D2190;

2

×

(c) T (d) T − 0D2190;

2

×

14. E90 gm of OH2 is vaporised at Co100 and 1

atm pressure9 !f the latent heat of vaporisation of

'ater is g ! + & then S∆ is given by

(a);F;

+ (b)

100

1D +

(c)

;F;

1D + (d)

;F;

1D

2

1 + ×

15. The S∆ for the vaporisation of 1 mol of 'ater is

DD9; !mole K 9 The value of S∆ for thecondensation of 1 mol of vapour 'ill be

(a) DD9; !mol K (b) 2);9DD( !mol K

(c) A DD9; !mol K (d);9DD

1 !mol K

16. #or 'hich reaction from the follo'ing& S∆ 'ill bema"imum

(a) )()(

2

1)( 2 'CaOgO'Ca →+

(b) )()()( 2; gCO'CaO'CaCO +→

(c) )()()( 22 gCOgO'C →+

(d) )(2)()( 22 gNOgOgN →+

17. The occurrence of a reaction is impossible if

(a) H∆ is Nve = S∆ is also N ve but

ST H ∆∆

(c) H∆ is A ve = S∆ is N ve

(d) H∆ is N ve = S∆ is A ve

18. !f the enthalpy of vapori/ation for 'ater is 1D95 !1−mol & the entropy of its vapori/ation 'ill be

(a) 11590 −− mol !K (b) 11091 −− mol !K

(c) 11591 −− mol !K (d) 11092 −− mol !K

19. .hich of the follo'ing statement is true9 Theentropy of the universe

(a) !ncreases and tends to'ards ma"imum value

(b) 7ecreases and tends to be /ero

(c) emains constant

(d) 7ecreases and increases 'ith a periodic rate

20. .hen enthalpy and entropy change for a chemical

reaction are cal;10592 ×− and calI9F

1deg− respectively9 -redict the reaction at

K 2ED is

(a) 3pontaneous (b) eversible

(c) !rreversible (d) *onLspontaneous

21. The total entropy change for a system and itssurroundings increases& if the process is

(a) eversible (b) !rreversible

(c) $"othermic (d) $ndothermic

22. #or chemical reactions& the calculation of changein entropy is normally done

(a) t constant pressure

(b) t constant temperature

(c) t constant temperature and pressure both

(d) t constant volume

23. .hen the value of entropy is greater& then theability of 'or,

(a) !s ma"imum (b) !s minimum

(c) !s medium (d) *one of these

24. .hich of the follo'ing is true for the reaction

)(2 lOH < )(2 gOH at Co100 and 1

atmosphere

(a) 0=∆E (b) 0=∆H

(c) EH ∆=∆ (d) ST H ∆=∆25. The enthalpy change for the transition of liuid

'ater to steam&1;9;F −=∆ mol!Ha- at

K ;F; 9 The entropy change for the process is

(a) 11E9111 −− K mol ! (b)

11;9;F

−− K mol !

(c) 11100 −− K mol ! (d) 11H9FI −− K mol !

26. .hen a solid is converted into liuid& entropy

(a) 4ecomes /ero (b) emains the same

(c) 7ecreases (d) !ncreases

27. !n a spontaneous process& the entropy of thesystem and its surroundings

(a) $uals /ero (b) 7ecreases

(c) !ncreases (d) emains constant

28. The positive value of S∆ indicates that(a) The system becomes less disordered

(b) The system becomes more disordered

(c) The system is in euilibrium position

(d) The system tends to reach at euilibriumposition

29. #or reaction )()(2 2 'Cl'Cl → & the signs of H∆and S∆ respectively are

(a) N& A (b) N& N

(c) A& A (d) A& N

30. The enthalpy of 'ater is !;DH 9 .hat is entropy

of 'ater

(a) 095 ! (b) 190; !


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(c) 195 ! (d) 22905 !

31. #or 'hich of the processes is S∆ negative

(a) )(2)(2 gHgH →

(b) atmgNatmgN D)(1)( 22 →

(c) )()(2)(2 22; gOgSOgSO +→

(d) )()( gra-./ted/amond CC →

32. !dentify the correct statement regarding entropy

(a) t Co0 & the entropy of a perfectly crystallinesubstance is ta,en to be /ero

(b) t absolute /ero of temperature& the entropy

of a perfectly crystalline substance is ,e+ (c) t absolute /ero of temperature& the entropy

of all crystalline substances is ta,en to be /ero

(d) t absolute /ero of temperature& the entropyof a perfectly crystalline substance is ta,en to

be /ero33. 8ne mole of an ideal gas at K ;00 is e"panded

isothermally from an initial volume of 1 litre to 10litres9 The change in energy for this process is

)2( 11 −−= K molcalR

(a) 1;9F cal (b) D5092 cal

(c) 1;D191 cal (d) ero

34. !f g ! E00 of heat is e"changed at boiling point

of 'ater& then 'hat is increase in entropy

(a) I;9I !0mole (b) DF92 !0mole

(c) E00 !0mole (d) ero

35. container has hydrogen and o"ygen mi"ture in

ratio of I B 1 by 'eight& then(a) !nternal energy of the mi"ture decreases

(b) !nternal energy of the mi"ture increases

(c) $ntropy of the mi"ture increases

(d) $ntropy of the mi"ture decreases

36. !f 09F5 mole of an ideal gas e"pands isothermally

at Co2F from 15 l/tre' to 25 l/tre', the ma"imum

'or, obtained is

(a)D9I0 ! (b) E9;I !

(c) 109D ! (d) 109I; !

37. !n 'hich of the follo'ing conditions a chemicalreaction can not occur

(a) H∆ and S∆ increase and HST ∆>∆(b) H∆ and S∆ decrease and ST H ∆>∆

(c) H∆ increases and S∆ decreases

(d) H∆ decreases and S∆ increases

38. n engine operating bet'een Co150 and

Co25 ta,es 500 ! heat from a higher

temperature reservoir if there are no frictionallosses& then 'or, done by engine is

(a) 1IF9F ! (b) 15F9F5 !

(c) 159D5 ! (d) 1E9E5 !

39. The entropy of a perfectly crystalline solid atabsolute /ero is

(a)-ositive (b) *egative

(c) ero (d) *ot denite

40. .hich of the follo'ing conditions 'ill al'ays leadto a nonLspontaneous change

(a) -ositive H∆ and positive S∆

(b) *egative H∆ and negative S∆

(c) -ositive H∆ and negative S∆(d) *egative H∆ and positive S∆

41. #ollo'ing data is ,no'n about melting of a

compound *)9 129E −=∆ mol!H &1100D90 −−=∆ molK !S 9 !ts melting point is

(a) F; K (b) 1050 K

(c) K 1150 (d) Co1150

42. The volume of a gas decreases from cc500 to

cc;00 'hen a sample of gas is compressed by

an average pressure of 09 atm9 7uring thisprocess 10 ! of heat is liberated9 The change in

internal energy is(a) A 291 ! (b) 12915 !

(c) 291 ! (d) 1019; !

43. The standard entropies of )()&(2 'CgCO and

)(2 gO are 21;95& 59E0 and1205 − !K

respectively9 The standard entropy of formation of

)(2 gCO is

(a) 1DH91 − !K (b) 1EH91 − !K

(c) 1D192 − !K (d) 1DH92 − !K

44. .hich of the follo'ing endothermic processes arespontaneous

(a) elting of ice (b) $vaporation of 'ater

(c) Heat of combustion (d) 4oth (a) and (b)

45. #or the reaction )(2 'OH < )(2 lOH at Co0and normal pressure

(a) ST H ∆>∆ (b) ST H ∆=∆

(c) GH ∆=∆ (d) ST H ∆


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(a) 6iolates !st la' of thermodynamics

(b) 6iolates !st la' of thermodynamics if 1Q is A

e

(c) 6iolates !st la' of thermodynamics if 2Q is A

e

(d) 7oes not violate !st la' of thermodynamics

49. $ual volumes of monoatomic and diatomic gasesat same initial temperature and pressure aremi"ed9 The ratio of specic heats of the mi"ture

)( , - CC 'ill be

(a) 1 (b) 2

(c) 19F (d) 195

50. The la' formulated by 7r9 *ernst is

(a) #irst la' of thermodynamics

(b) 3econd la' of thermodynamics

(c) Third la' of thermodynamics

(d) 4oth (a) and (b)51. The unit of entropy is

(a) 1−mol ! (b) 1−mol !K

(c) 11 −− K mol ! (d) 111 molK ! −−

52. The entropy changed involved in the conversion of 1 mole of liuid 'ater at ;F; K to vapour at thesame temperature 'ill be

R25F92S vap gm!H =∆

(a) 0911E ! (b)0910E !

(c) 0912E ! (d) 09120 !

53..hen a liuid boils& there is(a) n increase in entropy

(b) decrease in entropy

(c) n increase in heat of vapori/ation

(d) n increase in free energy

54. .hich one of the follo'ing has oS∆ greater than/ero

(a) )(2 gCOCaO+ < )(; 'CaCO

(b) )(aqNaCl < )('NaCl

(c) )(; 'NaNO < )()( ; aqNOaqNa −++

(d) )(;)( 22 gHgN + < )(2 ; gNH

55. The molar heat capacity of 'ater at constant

pressure is 11F5 −− mol !K 9 .hen 190 ! of heat

is supplied to 100 g of 'ater 'hich is free toe"pand the increase in temperature of 'ater is

(a) 9 K (b) 192 K

(c) 29I K (d) I9D K

56. The 'or, done to contract a gas in a cylinder& isI2 #o$le'9 12D #o$le energy is evolved in theprocess9 .hat 'ill be the internal energy changein the process

(a) N 5E0 #o$le' (b) A ;;I #o$le'

(c) N ;;I #o$le' (d) A 5E0 #o$le'

57. Highest entropy is in

(a) Hydrogen (b) .ater

(c) Jraphite (d) ercury

58.F0

2F910)2ED(

)()()(11 +−

−+ → +

−−

lOHaqOHaqHmolK K So

3tandard entropy change for the above reaction is

(a) 11;9H0 −− mol !K (b) 11F9D0 −− mol !K

(c) 11F0 −−− mol !K (d) 11F910 −−+ mol !K

59. 8ne mole of 'ater at Co100 is converted into

steam at Co100 at a constant pressure of 1 atm9 The change in entropy is Sheat of vaporisation of

'ater at gmcalCo 5I0100 = R

(a) D9FI (b) 1D9F

(c) 2I90 (d) 290

60. #or a carnot engine& the source is at K 500 and

the sin, at K ;00 9 .hat is eciency of thisengine

(a) 092 (b) 09I

(c) 09 (d) 09;

61. Heat reuire to raise the temperature of 1 mol of a

substance by Co1 is called

(a) 3pecic heat (b) olar heat capacity

(c) .ater euivalent (d) 3pecic gravity

62. a"imum entropy 'ill be in 'hich of the follo'ing

(a) !ce (b) iuid 'ater

(c) 3no' (d) .ater vapours

63. The standard entropies of )()&(2 'CgCO and)(2 gO are 21;95& 59FI0 and 205 1− !K

respectively9 The standard entropy of formation of

2CO is

(a) 1FH92 − !K (b) 11292 − !K

(c) 11291 − !K (d) 1I091 − !K

64. .hich la' of thermodyanamics help in calculatingentropy at di+erent temperatures

(a) #irst la' (b) 3econd la'

(c) Third la' (d) eroth la'

65. $ntropy is ma"imum in case of

(a) 3team (b) .ater at Co0

(c) .ater at CoI (d) !ce

66. Considering entropy (3) as a thermodynamicparameter& the criterion for the spontaneity of anyprocess is

(a) 0>∆ '1'temS only

(b) 0>∆ g''$rro$nd/nS only

(c) 0>∆+∆ g''$rro$nd/n'1'tem SS

(d) 0>∆−∆ g''$rro$nd/n'1'tem SS

67. process is ta,ing place at constant temperatureand pressure9 Then


9/27


(a) EH ∆=∆ (b) ST H ∆=∆

(c) 0=∆H (d) 0=∆S68. The enthalpy of vapouri/ation of a liuid is

1;0

−mol! and entropy of vapouri/ation is

K mol ! 1F5 − 9 The boiling point of the liuid at 1

atm is

(a) 250K (b) I00K

(c) I50K (d) 00K

Heat of reaction

1. !f calCOOC 29EI22 +→+

calOHOH ;9HD2

1222 +→+

calOHCOOCH D921022 222I ++→+

then the possible heat of methane 'ill be

(a) IF9; cal (b) 2090 cal

(c) I59E cal (d) A IF9; cal

2. olar heat of vaporisation of a liuid is1

H −mol! 9 !f the entropy change is

111H

−− K mol ! & the boiling point of the liuid is

(a) Co;F5 (b) K ;F5

(c) K 2F; (d) Co102

3. The enthalpy of fusion of ice per mole

(a) 1D ! (b) D !(c) D0 ! (d) !

4. !n 'hich of the follo'ing neutralisation reactions&the heat of neutralisation 'ill be highest

(a) OHNHI and COOHCH;

(b) OHNHI and HCl

(c) NaOH and COOHCH;

(d) NaOH and HCl

5. !f )292ED(=22 −=∆→+ HSOOS

)29ED(=2

1;22

−=∆→+ HSOOSO

)291;0(=I22; −=∆→+ HSOHOHSO

);92DF(=2

1222 −=∆→+ HOHOH

then the enthalpy of formation of I2SOH at

2EDG 'ill be

(a) !F9I;;− (b) !;9H50−

(c) !59;20+ (d) !E9D1;−

6. #rom Girchho+%s euation 'hich factor a+ects theheat of reaction

(a) -ressure (b) Temperature

(c) 6olume (d) olecularity

7. The molar neutrali/ation heat for KOH and

;HNO as compared to molar neutrali/ation heat

of NaOH and HCl (a) ess (b) ore

(c) $ual (d) 7epends on pressure

8. n e"othermic reaction is one in 'hich thereacting substances

(a) Have more energy than the products

(b) Have less energy than the products

(c) re at a higher temperature than the product

(d) *one of the above

9. The heat evolved in the combustion of ben/ene isgiven by

!HlOHgCOOHC H9;2HI)=(;)(H2

1F 222HH −=∆+→+

.hich of the follo'ing uantities of heat energy

'ill be evolved 'hen HH;E HCg are burnt(a) D1915 ! (b) 1;29; !

(c) 52D92 ! (d) 2IID9I5 !

10. Thermochemical reactions

!HgCOgOC 59110)=()(2

1)graphite( 2 −=∆→+

!HgCOgOgCO 292D;)=()(2

1)( 22 −=∆→+

#rom the above reaction& the heat of reaction for

)()()graphite( 22 gCOgOC →+ 'ill be

(a) A ;E;9F ! (b) N ;E;9F !

(c) A 1F29F ! (d) N 1F29F !

11. The follo'ing is (are) endothermic reaction

(a) Combustion of methane

(b) 7ecomposition of 'ater

(c) 7ehydrogenation of ethane to ethylene

(d) Conversion of graphite to diamond

12. $vaporation of 'ater is

(a) n endothermic change

(b) n e"othermic change

(c) process 'here no heat change occurs

(d) process accompanied by chemical reaction

13. n e"othermic reaction is one 'hich

(a) Ta,es place only on heating

(b) !s accompanied by a Qame

(c) !s accompanied by a absorption of heat

(d) !s accompanied by evolution of heat

14. n endothermic reaction is one in 'hich

(a) Heat is converted into electricity

(b) Heat is absorbed

(c) Heat is evolved

(d) Heat is converted into mechanical 'or,

15. .hich of the follo'ing statement is correct

(a) H∆ is positive for e"othermic reaction

(b) H∆ is negative for endothermic reaction(c) The heat of neutrali/ation of strong acid and

strong base is al'ays the same(d) The enthalpy of fusion is negative


10/27

167 Thermodynamics and Thermochemistry16. The absolute enthalphy of neutralisation of the

reaction

)()()(2)( 22 lOHaq2gClaqHCl'2gO +→+ '

ill be

(a)ess than 1;;95F −− mol!

(b) 1;;95F −− mol!

(c) Jreater than 1;;95F −− mol!

(d) 1;;95F −mol!

17. 3 H°∆ (2ED K ) of methanol is given by the

chemical euation

(a) )()(21)( ;2I gOHCHgOgCH →+

(b) C (graphite)

)()(2)(21 ;22 lOHCHgHgO →++

(c) C (diamond)

)()(2)(21 ;22 lOHCHgHgO →++

(d) )()(2)( ;2 lOHCHgHgCO →+

18. !fo3 H∆ for 22OH and OH2 are

mole! 1DD− and mol! 2DH− 9 .hat 'ill

be the enthalpy change of the reaction

)()(2)(2 2222 gOlOHlOH +→

(a) mole! 1EH− (b) mole! 1IH

(c) mole! IEI− (d) mole! ED−

19. The heat of transition )( t H∆ of graphite into

diamond 'ould be& 'here

! + HgCOgOC =∆→+ )=()()graphite( 22

! 1 HgCOgCC =∆→+ )=()()diamond( 22

(a) 1)( −+ mol! 1 + (b) 1)( −− mol! 1 +

(c) 1)( −− mol! + 1 (d) *one of these

20. Correct relationship bet'een heat of fusion

)( 3$'H∆ & heat of vapori/ation )( a-H∆ and

heat of sublimation )( '$4H∆ is

(a) '$4,a-3$' HHH ∆+∆=∆

(b) '$43$',a- HHH ∆+∆=∆

(c) 3$',a-'$4 HHH ∆+∆=∆

(d) 3$',a-'$4 HHH ∆−∆=∆

21. .hich of the follo'ing is an e"ample of endothermic reaction

(a) !EHCHHC 09;1I=2 H2222 −=∆→+

(b) !ECOOC 59;E;=22 −=∆→+

(c) !ENOON 591D0=222 −∆→+

(d) !EOHOH D95F1=22 222 +∆→+

22. !f the enthalpy of 4 is greater than of *& the

reaction ) *→ is

(a) $ndothermic (b) $"othermic

(c) !nstantaneous (d) 3pontaneous

23. Jiven that

!HgCOgO'C FDF)=(2)(2)(2 22 −=∆→+

!HlOHgOgH 2DH)=()(2

1)( 222 −=∆→+

HlOHgCOgOgHC 1;01)=()(2)(2

12)( 22222 −=∆+→+

Heat of formation of acetylene is

(a) !1D02− (b) !1D02+

(c) !D00− (d) !22D+

24. $nthalpy change for reaction&

HClClH →+ 222

1

2

1& is called

(a) $nthalpy of combination (b) $nthalpy of reaction

(c) $nthalpy of formation(d) $nthalpy of fusion25. The enthalpy of neutrali/ation is about 5F9; ! for

the pair

(a) HCl and OHNHI

(b) OHNHI and ;HNO

(c) HCl and NaOH

(d) COOHCH; and NaOH

26. Conversion of o"ygen to o/one represented by the

euation ;2 2; OO → is an endothermic reaction9

$nthalpy change H∆ accompanying the reaction(a) !s negative

(b) !s positive(c) !s /ero

(d) 7epends on temperature

27. The mutual heat of neutralisation of I0 gm of

NaOH and 0 gm COOHCH; 'ill be

(a) 591 cal (b) ess than 591 cal

(c) ore than 591 cal (d) 1;9F cal

28. The heat of formations of )(gCO and )(2 gCO

are I92H− cal and 09EI− cal respectively9 The heat of combustion of carbon mono"ide 'illbe

(a) calI92H+ (b) calH9HF−

(c) calH9120− (d) calD952+

29. The enthalpy of combustion at 25UC of H2&cyclohe"ane (CH12) and cyclohe"ene (CH10) are A2I1& A;E20 and AD00 K! 0 mole respectively9 Theheat of hydrogenation of cyclohe"ene is

(a) A 121 K! mole (b) N 121 K! mole

(c) A 2I2 K! 0 mole (d) N 2I2 K! 0 mole

30. Heat of neutralisation of OHNHI and HCl is

(a) calF91; (b) calF91;>

(c) caF91;< (d) *one of the above

31. Heat of combustion H∆ of I2H2I && HCHCCH and 22HC gases are A


11/27


2129D& A ;F;90& A ;;F90 and A ;1095 calrespectively at the same temperature9 The bestfuel among these gases is

(a) ICH (b) H2HC

(c) I2HC (d) 22HC

32. Heat of formation of )()&( 22 lOHgCO and

)(I gCH are A EI90& A D9I and A 1F9E cal

respectively9 The heat of combustion of methane is

(a) A 2129E cal (b) A 1;9D cal

(c) A ;0I9; cal (d) A 10592 cal

33. The heat of reaction does not depend upon

(a) Temperature of the reaction

(b) -hysical state of reactants and products

(c) .hether the reaction is carried out at constantpressure or at constant volume

(d) The method by 'hich the nal products areobtained from the reactants

34. Heat of neutralisation of a strong acid by a strongbase is a constant value because

(a) 3alt formed does not hydrolyse

(b) 8nly +H and −OH ions react in every case

(c) The strong base and strong acid reactcompletely

(d) The strong base and strong acid react inaueous solution

35. Heat of neutralisation of an acid by a base ishighest 'hen

(a) 4oth the acid and base are 'ea,

(b) 4oth the acid and base are strong

(c) The acid is strong and the base is 'ea,(d) The acid is 'ea, and the base is strong

36. The standard molar heat of formation of ethane&

2CO and 'ater (l) are respectively A 2191& A EI91and A D9; cal9 The standard molar heat of combustion of ethane 'ill be

(a) A ;F2 cal (b) 12 cal

(c) A2I0 cal (d) 1D;95 cal

37. .hich of the follo'ing reaction is endothermic

(a) 2; COCaOCaCO +→

(b) 5eSS5e →+

(c) OHNaClHClNaOH

2+→+

(d) OHCOOCH 222I 22 +→+

38. !n the reaction

!HgOHgCOgHgCO D0)=()()()( 222 =∆+→+

H∆ is ,no'n as

(a) Heat of formation (b) Heat of combustion

(c) Heat of neutrali/ation (d) Heat of reaction

39. Heat of combustion of a substance

(a) !s al'ays positive

(b) !s al'ays negative

(c) !s eual to heat of formation(d) *othing can be said 'ithout reaction

40. The heat change for the reaction

OHOH 2222

1→+ is called

(a) Heat of reaction (b) Heat of formation

(c) Heat of vaporisation (d) *one of the above

41. The heat change H∆ for the reaction

calHCOOCO 1;5=22 22 −=∆→+ is called

(a) Heat of formation (b) Heat of reaction

(c) Heat of combustion (d) Heat of solution

42. The heats of combustion of rhombic andmonoclinic sulphur are respectively F0E0 andF10;0 calories9 .hat 'ill be the heat of conversion of rhombic sulphur to monoclinic

(a) F0E0 calories (b) F10;0 calories

(c) A F0 calories (d) N F0 calories

43. The heat of formation of )(2 lOH is A D90 cal&the heat of formation of )(2 gOH is li,ely to be

(a) A D90 cal (b) A F9I cal

(c) D090 cal (d) A 5D9; cal

44. .hich of the follo'ing fuels 'ill have the highestcaloric value (!0g)

(a) Charcoal (b) Gerosene

(c) .ood (d) 7ung

45. The heat of combustion of carbon is AEI cal at 1

atm pressure9 The intrinsic energy of 2CO is

(a) calEI+ (b) calEI−

(c) calIF+

(d) calIF−

46. The heat of neutralisation of a strong acid and a

strong al,ali is 1095F −mol! 9 The heat

released 'hen mol590 of ;HNO solution is

mi"ed 'ith mole290 of KOH is

(a) !095F (b) !I911

(c) !592D (d) !E9;I

47. solution of ml500 of KOH2290 andml500 of HCl2290 is mi"ed and stirred=

the rise in temperature is 1T 9 The e"periment is

repeated using ml250 each of solution& the

temperature raised is 2T 9 .hich of the follo'ing

is true

(a) 21 T T = (b) 21 2T T =

(c) 21 IT T = (d) 12 ET T =

48. $nthalpy of a compound is eual to its

(a) Heat of combustion (b) Heat of formation

(c) Heat of reaction (d) Heat of solution

(e) Heat of dilution

49. .hich is the best denition of >heat of neutrali/ation?

(a) The heat set free 'hen one gram molecule of a base is neutrali/ed by one gram molecule of


12/27


an acid in dilute solution at a statedtemperature

(b) The heat absorbed 'hen one gram molecule of an acid is neutrali/ed by one gram moleculeof a base in dilute solution at a statedtemperature

(c) The heat set free or absorbed 'hen one gramatom of an acid is neutrali/ed by one gramatom of a base at a stated temperature

(d) The heat set free or absorbed 'hen a normalsolution containing one gram euivalent of anacid is neutrali/ed by a normal solutioncontaining one gram euivalent of a base at astated temperature

(e) The heat set free 'hen one gram euivalent of an acid is neutrali/ed by one gram euivalentof a base in dilute solution at a statedtemperature

50. The compound 'ith negative heat of formation are

,no'n as(a) $ndothermic compound

(b) $"othermic compound

(c) Heat of formation compound

(d) *one of the above

51. !f calOHOHH F91;2 +→+ −+ & then the heat

of neutrali/ation for complete neutrali/ation of one

mole of I2SOH by base 'ill be

(a) 1;9F cal (b) 2F9I cal

(c) 9D5 cal (d) ;9I25 cal

52. The lo'est value of heat of neutrali/ation is

obtained for(a) NaOHHCl +

(b) OHNHCOOHCH I; +

(c) HClOHNH +I

(d) COOHCHNaOH ;+

53. Heat of neutralisation for the given reaction

OHNaClHClNaOH 2+→+ is1

195F −mol!

9 .hat 'ill be the heat released 'henmole2590 of NaOH is titrated againstmole2590 of HCl

(a) 15922 −mol! (b) 1195F −mol!

(c) 1;91I −mol! (d) 1H92D −mol!

54. eaction& )(2)()( 22 gHIgIgH →+

calH I0912−=∆ 9 ccording to this& the heat

of formation of HI 'ill be

(a) 129I cal (b) A 129I cal

(c) A 920 cal (d) 920 cal

55. ll reactions 'ith chemical dissociation are

(a) eversible

(b) eversible and endothermic(c) $"othermic

(d) eversible or irriversible and endothermic ore"othermic

56. The heat of formation is the change in enthalpyaccompanying the formation of a substance fromits elements at 2ED K and 1 atm pressure9 3incethe enthalpies of elements are ta,en to be /ero&

the heat of formation )( H∆ of compounds

(a) !s al'ays negative

(b) !s al'ays positive

(c) ay be negative or positive

(d) !s /ero

57. The heat of combustion of )graphite()(I &CCH g

and )(2 gH are calcal I0&20 − and

cal10− respectively9 The heat of formation of

methane is

(a) cal09I− (b) calI0+

(c) caD0− (d) calD0+58. !f a chemical reaction is accompanied by the

evolution of heat& it is

(a) Catalytic (b) -hotochemical

(c) $ndothermic (d) $"othermic

59. reaction that ta,es place 'ith the absorption of energy is

(a) 4urning of a candle (b) usting of iron

(c) $lectrolysis of 'ater (d) 7igestion of food

60. .hich of the follo'ing is an endothermic reaction

(a) OHOH 222 22 →+

(b) NOON 222 →+

(c) OHSONaSOHNaOH 2I2I2 22 +→+

(d) OHCOOHHCO 22522 ;2; +→+

61. 8ne of the phenomena 'hich cannot be describedas combustion is

(a) 8"idation of coal in air

(b) 4urning of magnesium in nitrogen

(c) eaction of antimony in chlorine

(d) ighting of an electric lamp

62. .hich of the follo'ing statements is correct aboutheat of combustion

(a) !t may be e"othermic in some cases andendothermic in other cases

(b) !t is applicable to gaseous substances only

(c) !t is al'ays an e"othermic reaction

(d) !ts value does not change 'ith temperature

63. calHOHOH ;E9HD=2

1222 −=∆→+

++ OHK 2 .ater

calHHaqKOH ID=2

1)( 2 −=∆+→

+KOH .ater calHaqKOH 1I)=( −=∆→


13/27


The heat of formation of KOH is (in cal)

(a) 1IID;E9HD −+− (b) 1IID;E9HD +−−

(c) 1IID;E9HD +− (d) D9;E N ID N 1I

64. .hich of the follo'ing reaction can be used to

dene the heat of formation of )(2 gCO(a) )()((graphite) 22 gCOgOC =+

(b) )(2)()(2)( 222I lOHgCOgOgCH +=+

(c) )()(2

1)( 22 gCOgOgCO =+

(d) )(;H)(2

1F)( 222HH lOHCOgOlHC +=+

65. The enthalpy of formation of ammonia is1

09IH −

− mol! 9 The enthalpy change for the

reaction )(;)(2)(2 22; gHgNgNH +→ is

(a) I90 ! 1−mol (b) E290 ! 1−mol

(c) A 2;90 ! 1−mol (d) A E290 ! 1−mol66. The heat of combustion of ben/ene determined in

a bomb calorimeter is 1DF0 −− molcal at

Co25 9 The value of E∆ for the reaction is

(a) cal1FI0− (b) caDF0−

(c) calDF2− (d) caDFI−

67. The formation of 'ater from )(2 gH and )(2 gO

is an e"othermic reaction because

(a) The chemical energy of )(2 gH and )(2 gOis more than that of 'ater

(b) The chemical energy of )(2 gH and )(2 gO

is less than that of 'ater

(c) *ot dependent on energy

(d) The temperature of )(2 gH and )(2 gO is

more than that of 'ater

68. !n the reaction for the transition of carbon in thediamond form to carbon in the graphite form&

H∆ is cal59I5;− 9 This points out that

(a) Jraphite is chemically di+erent from diamond

(b) Jraphite is as stable as diamond

(c) Jraphite is more stable than diamond

(d) 7iamond is more stable than graphite

69. !n the combustion of hydrocarbons& H∆ is

(a) *egative (b) ero

(c) -ositive (d) ndeterminate

70. The standard heats of formation in cal 1−mol of

)(2 gNO and )(I2 gON are D90 and 290

respectively9 The heat of dimeri/ation of 2NO in

ca is

)()(2 I22 gONgNO =

(a) 1090 (b) A 90(c) A 1290 (d) A 1I90

71. The di+erence bet'een heats of reaction atconstant pressure and at constant volume for thereaction

)(H)(12)(15)(2 222HH lOHgCOgOlHC +→+

at Co25 in ! is

(a) AF9I; (b) N ;9F2(c) A;9F2 (d) N F9I;

72. C (diamond) ;E5)=()( 22 −=∆→+ HgCOgC

!

C (graphite)59;E;)=()( 22 −=∆→+ HgCOgO !

#rom the data& the H∆ 'hen diamond is formedfrom graphite& is

(a) !591− (b) !591+

(c) !09;+ (d) !09;−

73. .hich of the follo'ing values of heat of formationindicates that the product is least stable

(a) calEI− (b) calH92;1−

(c) calI921+ (d) calD9HI+

74. .hich of the follo'ing euations correctlyrepresents the standard heat of formation

)( o3 H∆ of methane

(a) )()(2)( I2 gCHgHd/amond C =+

(b) )()(2)( I2 lCHgHgra-./teC =+

(c) )()(2)( I2 gCHgHgra-./teC =+

(d) )(I)( I gCHHgra-./teC =+

75. !n 'hich of the follo'ing reactions does the heatchange represent the heat of formation of 'ater

(a)

calHlOHgOgH 11H)=(2)()(2 222 −=∆→+

(b)

calHlOHgOgH 5D)=()(2

1)( 222 −=∆→+

(c)

calHlOHaqOHaqH F91;)=(29)(9)( 2 −=∆→+ −+

(d) )()(2)(

2

12)(

22222 lOHgCOgOgHC +→+

=

calH ;10−=∆

76. 6alues of heats of formation for 2S/O and 2gO

are I9ID− and !F9;I− respectively9 The

heat of the reaction S/2gOS/O2g +→+ 22 2 is

(a) !1H921 (b) !10921−

(c) !H291;− (d) !H91;

77. 4ased on the follo'ing thermochemical euations

!HgHgCO'CgOH 1;1)=()()()( 22 =∆+→+


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!HgCOgOgCO 2D2)=()(2

1)( 22 −=∆→+

!HgOHgOgH 2I2)=()(2

1)( 222 −=∆→+

! % HgCOgO'C =∆→+ )=()()( 22

The value of % is(a) !;E;− (b) !H55−

(c) !;E;+ (d) !H55+

78. Heat of transition is the heat evolved or absorbed'hen a substance is converted from

(a) 3olid to liuid

(b) 3olid to vapour

(c) iuid to vapour

(d) 8ne allotropic form to another allotropic form

79. #or the allotropic change represented by euation

)()( gra-./t Cd/amond C → = the enthalpychange is !H DE91−=∆ 9 !f gH of diamond

and gH of graphite are separately burnt to yield

carbon dio"ide& the heat liberated in the rst caseis

(a) ess than in the second case by !DE91

(b) ore than in the second case by !DE91

(c) ess than in the second case by !;I911

(d) ore than in the second case by !EI590

80. #or an e"othermic reaction

(a) H of the products is less than H of thereactants

(b) H of the products is more than H of thereactants

(c) H of the products is eual to H of thereactants

(d) H∆ is al'ays positive

81. The energy evolved is highest for 'hich of thefollo'ing reactions

(a) 1−− →+ 5 e5 (b) −− →+ CleCl

(c) −− →+ 22 SeS (d) −− →+ 22 OeO

82. !n the combustion ofgm092

of methanecal25 heat is liberated& heat of combustion of

methane 'ould be

(a) cal100 (b) cal200

(c) cal;00 (d) calI00

83. Complete combustion of ICH gives

(a) OHCO 22 + (b) 22 HCO +

(c) 2COCl (d) OHCOCO 22 ++

84. !f enthalpies of formation of )()&( 2I2 gCOgHC

and )(2 lOH at Co25 and at 1 pressure be

52& A ;EI and 12DH −− mol! respectively& the

enthalpy of combustion of )(I2 gHC 'ill be

(a) 11I12 −+ mol! (b) 11I12 −− mol!

(c) 1291I1 −+ mol! (d) 1291I1 −− mol!

85. Carbon and carbon mono"ide burn in o"ygen toform carbon dio"ide according to the follo'ingreactions

122 ;EI=

−−=∆→+ mol!HCOOC

122 5HE=22 −

−=∆→+ mol!HCOOCO

The heat of formation of mol1 of carbon

mono"ide is thus

(a) 10921E −− mol! (b) 15910E −− mol!

(c) 1091F5 −− mol! (d) 159DF −− mol!

86. Heat of formation in the reaction

calHClClH II222 +→+ is

(a) II cal (b) II000 cal

(c) 22 cal (d) 11 cal

87. .hen 'ater is added to uic, lime& the reaction is

(a) $"othermic (b) $ndothermic

(c) $"plosive (d) *one of these

88. !n an e"othermic reaction H∆ is

(a) -ositive (b) *egative

(c) ero (d) 4oth positive ornegative

89. The heat change for the follo'ing reaction

)()(2)( 2 lCS'S'C →+ is ,no'n as

(a) Heat of vapori/ation (b) Heat of solution

(c) Heat of fusion (d) Heat of formation

90. The enthalpy of combustion of ben/ene from thefollo'ing data 'ill be

(i)

!HlHCgH'C E9I5)=()(;)(H HH2 +=∆→+

(ii)

!HlOHgOgH E92D5)=()(2

1)( 222 −=∆→+

(iii) !HgCOgO'C 59;E;)=()()( 22 −=∆→+(a) N ;1F29D ! (b) A 15IE92 !

(c) A ;1F29D ! (d) A ;2I9 !

91. $nthalpy of formation of H5 and HCl are!1H1− and !E2− respectively9 .hich of

the follo'ing statements is incorrect

(a) HCl is more stable than H5

(b) H5 and HCl are e"othermic compounds

(c) The anity of Quorine to hydrogen is greaterthan the anity of chlorine to hydrogen

(d) H5 is more stable than HCl


15/27


92. The heat of reaction at constant pressure is givenby

(a) RP EE − (b) PR EE −

(c) RP HH − (d) PR HH −

93. !n an endothermic reaction& the value of H∆ is(a) ero (b) -ositive

(c) *egative (d) Constant

94. g201H92 of acetaldehyde produced

calE591; of heat on combustion in 2O 9

Calculate the heat of combustion of CHOCH;

(a) 2FE cal (b) EF2 cal

(c) 2F9E cal (d) 29FE cal

95. !HCOOC I2=2

12 −=∆→+

!HCOOCO 2I=2

122 −=∆→+

The heat of formation of 2CO is

(a) A 1 ! (b)N !

(c) N 1 ! (d) A !

96. 3tandard molar enthalpy of formation of 2CO is

eual to

(a) ero

(b) The standard molar enthalpy of combustion of gaseous carbon

(c) The sum of standard molar enthalpies of

formation of CO and 2O

(d) The standard molar enthalpy of combustion of carbon (graphite)

97. !n the complete combustion of butanol

)(EI lOHHC & if H∆ is enthalpy of combustion

and E∆ is the heat of combustion at constantvolume& then

(a) EH ∆∆

(d) EH ∆∆ & relation cannot be predicted

98. % HCOOC =∆→+ =22

6 HCOOCO =∆→+ =2

122

Then the heat of formation of CO is

(a) 6 % − (b) % 6 2−

(c) 6 % + (d) 6 % −2

99. The values of heat of formation of 2SO and

;SO are !292ED− and !29ED− 9 The

heat of reaction of the follo'ing reaction 'ill be

;222

1SOOSO →+

(a) !200− (b) !29;5H−

(c) !200+ (d) !29;EH−

100. Calculate the standard heat of formation of carbondisulphide )(l & given that the standard heat of

combustion of carbon )(' & sulphur )(' and

carbon disulphide )(l are F292E;&;9;E; −−

and 1FH9110D −− mol! respectively

(a) 102912D −− mol! (b)

1D02912

−+ mol!

(c) 102912D −+ mol! (d)

1D02912

−− mol!

101. #ermentation is a reaction called

(a) $ndothermic (b) $"othermic(c) !sotemperature (d) eversible

102. gmD of ICH is completely burnt in air9 The

number of moles of 'ater produced are

(a) 095 (b) 1

(c) 2 (d) 1D

103. #or the reaction

)(;)(2)(2)( g(gCg)g * +→+ & the value of

E∆ at Co2F is 1E90 cal9 The value of H∆ for

the reaction 'ould be )092( 11 −−= molK calR

(a) 209D cal (b) 1E9D cal

(c) 1D9D cal (d) 2092 cal104. The enthalpy of solution of )(2 ')aCl and

)(29 22 'OH)aCl are H920− and1

D9D −mol! respectively9 The enthalpy change

for the reaction →+ OH')aCl 22 2)( is

(a) 2E9I ! (b) A 119D !

(c) A 209 ! (d) A 2E9I !

105. The enthalpy change of a reaction does notdepend on

(a) The state of reactants and products

(b) *ature of reactants and products

(c) 7i+erent intermediate reaction

(d) !nitial and nal enthalpy change of a reaction

106. cal + SOOS 22

;;2 +→+

cal 1 SOOSO +→+ ;222

1

#ind out the heat of formation of 2SO

(a) 1 + −2 (b) 1 + +2

(c) 1 + + (d) 1 + 2

107. The combustion enthalpies of carbon& hydrogen

and methane are 159;E5 −− mol! &


16/27

173 Thermodynamics and Thermochemistry1

D92D5 −

− mol! and 1I9DE0 −− mol!

respectively at Co25 9 The value of standard

formation enthalpies of methane at thattemperature is

(a)1

I9DE0 −

mol! (b)1

D92ED −

− mol!

(c) 1F9FI −− mol! (d) 1F910F −− mol!

108. $ual volumes of methanoic acid and sodium

hydro"ide are mi"ed9 !f + is the heat of formationof 'ater& then heat evolved on neutralisation is

(a) ore than + (b) $ual to +

(c) T'ice of + (d) ess than + 109. The neutralisation of a strong acid by a strong

base liberates an amount of energy per mole of

+H that(a) 7epends upon 'hich acid and base are

involved

(b) 7epends upon the temperature at 'hich thereaction ta,es place

(c) 7epends upon 'hich catalyst is used

(d) !s al'ays the same

110. .hen g590 of sulphur is burnt to !SO H9I&2of heat is liberated9 .hat is the enthalpy of formation of sulphur dio"ide

(a) N 1IF92 ! (b) A 1IF92 !

(c) A 2EI9I ! (d) N 2EI9I !

111. 8/one is prepared by passing silent electricdischarge through o"ygen9 !n this reaction

(a) $nergy is given out

(b) $nergy is absorbed

(c) 8"ygen is loaded 'ith energy

(d) 8"ygen is dissociated into atoms

112. Combustion of glucose ta,es place according tothe euation&

OHCOOOHC 222H12H HHH +→+ &

calH F2−=∆ 9 Ho' much energy 'ill be

reuired for the production of 19 g of glucose(olecular mass of glucose K 1D0 g)

(a) 090I cal (b) 09I cal

(c) 9I cal (d) I cal

113. Jiven that

!HgCOgO'C ;EI)&()()( 22 −=∆→+

!HlOHgOgH 5HD)&(2)()(2 222 =∆→+

)(2)()(2)( 222I lOHgCOgOgCH +→+

!H DE2−=∆

Heat of formation of ICH is[DCE 1999]

(a) A F0 ! (b) F19D !

(c) A 2II ! (d) N FD2 !

114. Calculate the heat of formation of )(5 'PCl fromthe follo'ing data

calHlPClgCl'P D9151)=(2)(;)(2 ;2 −=∆→+

calH'PClgCllPCl D9;2)=()()( 52; −=∆→+

(a) A 10D9F cal (b) N 10D9F cal(c) A 1DI9 cal (d) N 1DI9 cal

115. .hen ;50cm of a strong acid is added to;

50cm of an al,ali& the temperature rises by

Co5 9 !f;250cm of each liuid are mi"ed& the

temperature rise 'ould be

(a) Co5 (b) Co10

(c) Co25 (d) Co20

116. )()(2

1)( 222 lOHgOgH →+ =

H∆ at 2ED K K A 2D59D ! The molar enthalpy of vaporisation of 'ater at 1

atm and Co25 is II !9 The standard enthalpy of

formation of 1 mole of 'ater vapour at Co25 is

(a) A 2I19D ! (b) 2I19D !

(c) ;2E9D ! (d) A;2E9D !

117. .hen I g of iron is burnt to ferric o"ide at constantpressure& 2E92D ! of heat is evolved9 .hat is theenthalpy of formation of ferric o"ide (t9 .t9 of 5eK 5)

(a) A D19ED ! (b) A D1E9D !

(c) A I09EE ! (d) N D1E9D !

118. .hen a strong acid& strong base or their salt aredissolved in 'ater& they are completely ionised9 !f

a strong acid is added to a strong base& +H ions

from the former combine 'ith −OH ions of thelatter forming 'ater9 The formation of each 'atermolecule liberates a certain uantity of energyand the reaction is e"othermic9 The heat liberated'hen one mole of 'ater is formed by combininghydrochloric acid and sodium hydro"ide is 1;9Fcal9 The heat liberated 'hen one mole of 'ater isformed by combining sulphuric acid and sodiumhydro"ide is

(a) 2595 cal (b) D95 cal

(c) 1;9F cal (d) ;I cal119. 291 g of 5e combines 'ith S evolving ;9FF !9 The

heat of formation of 5eS in !mol is

(a) A 19FE (b) A 10095

(c) A ;9FF (d) *one of these

120. !n the reactionB

!HHClClH 1EI&222 =∆→+ 9 Heat of

formation of HCl is

(a) N EF ! (b) N 1EI !

(c) A 1EI ! (d) A EF !

121. $nthalpy of neutralisation of acetic acid by

NaOH is9H950

mol!−

and the heat of neutralisation of a strong acid 'ith a strong base


17/27


is A 559E !mol9 .hat is the value of H∆ for the

ionisation of COOHCH;

(a) N 59; !mol (b) N 92 !mol

(c) N D92 !mol (d) N E9; !mol

122.Heat of neutrali/ation of the acidLbase reaction is5F9;2 ! for

(a) &/OHHNO +; (b) KOHHCOOH +

(c) OHNHHCl I+ (d)

NaOHCOOHCH +;

123. The heat change for the follo'ing reaction at

K o2ED and at constant pressure is cal;9F+

)(21)(2)( 22 g)' *') * +→ &

calH ;9F+=∆

The heat change at constant volume 'ould be

(a)F9; cal (b) ore than F9;(c) ero (d) *one of these

124. The heat evolved in the combustion of ben/ene isgiven by the euation

)(H)(;)(2

1F)( 222HH gCOlOHgOlHC +→+

109FD1 −=∆ molcalH

.hich of the follo'ing uantities of heat energy'ill be evolved 'hen ;E g of ben/ene is burnt inan open container

(a) 122925 cal 1−mol (b) ;E095 cal 1−mol

(c) 15290 cal 1−mol (d) 5D9F5 cal 1−mol

125. calHgHClgClgH II9)(2)()( 22 −=∆→+

)&()(2)(2)(2 2 gH'NaClgHCl'Na +→+

calH 152−=∆

#or the reaction

=∆→+ H'NaClgCl'Na )&()(2

1)( 2

(a) A 10D cal (b) A 1E cal

(c) A ED cal (d) 5I cal

126. The

o

3 H∆ for )()&(2 gCOgCO and )(2 gOHare A ;E;95& A11095 and A 2I19D!molA1

respectively9 The standard enthalpy change (in !)

for the reaction →+ )()( 22 gHgCO

)()( 2 gOHgCO + is

(a) 52I91 (b) I192

(c) A 2295 (d) A I192

127. .hich of the follo'ing compounds 'ill absorb thema"imum uantity of heat 'hen dissolved in thesame amount of 'ater : The heats of solution of

these compounds at Co25 in !mole of each

solute is given in brac,ets

(a) );;(; −=∆HHNO (b)

)HI91F( +=∆HKCl

(c) )5925(;I +=∆HNONH (d)

)19FI( −=∆HHCl

128. !n the reaction HHCSSC ∆∆+→+ &2 2 is the

(a) Heat of combustion (b) Heat of neutralisation

(c) Heat of solution (d) *one of these

129. The heat of formation of methane

)()(2)( I2 gCHgH'C →+ at constant pressure

is 1D500 cal at Co25 9 The heat of reaction at

constant volume 'ould be

(a) 1FE0I cal (b) 1D202 cal

(c) 1DFED cal (d) 1E0E cal

130. The enthalpy of combustion of )(HH lHC is A

;250 !9 .hen 09;E g of ben/ene is burnt e"cessof o"ygen in an open vessel& the amount of heatevolved is

(a) 1925 ! (b) 1925 !

(c) ;295 ! (d) ;295 !

131. calHCOgO'C EI=)()( 22 −=∆→+

calHCOgOgCO 291;5=)(2

1)( 22 =∆→+

Then heat of formation of )(gCO is (a)A 29I cal (b) I192 cal

(c) 29I cal (d) A 22E92 cal

132. The heat of neutrali/ation of HCl and NaOH is

(a) ero (b) A 5F9; !

(c) N 5F9; ! (d) *one of these

133. The follo'ing thermochemical reactions are given

!2OO2 I9;512

12 +→+

! %OO % D9E02

12 +→+

!t follo's that the heat of reaction for the follo'ing

process %O2 + < % 2O+ is given by

[AMU 2001]

(a) I2292 ! (b) 2D9F !

(c) A II292 ! (d) 209 !

134. !f the heat of combustion of carbon mono"ide at

constant volume and at Co1F is A 2D;9; !& then

its heat of combustion at constant pressure

)degree;1I9D( 1L1 −= mol !R

(a) A 2DI95 ! (b) 2DI95 !

(c) ;DI95 ! (d) A ;DI95 !

135. Heat of formation of OH 2 is mole! 1DD−

and 22OH is 92DH mole!− The enthalpy


18/27


change for the reaction 2222 22 OOHOH +→ is

(a) 1E ! (b) A 1E !

(c) EDI ! (d) A EDI !

136. The values of H∆ for the combustion of etheneand ethyne are A ;I191 and A ;1090calrespectively9 .hich of the follo'ing is a better fuel

(a) 22HC (b) I2HC

(c) 4oth of these (d) *one of these

137. #or e"othermic reaction& the euilibrium constant

(a) !ncreases 'ith increase of P

(b) 7ecreases 'ith increase of P

(c) !ncreases 'ith increase of temperature

(d) 7ecreases 'ith increase of temperature

138. !n order to decompose E g 'ater 1I295 ! heat isreuired9 Hence the enthalpy of formation of 'ateris

(a) A 1I295 ! (b) N 1I295 !

(c) A 2D5 ! (d) N 2D5 !

139. .hat is n∆ for combustion of 1 mole of ben/ene&

'hen both the reactants and the products are gasat 2ED K

(a) 0 (b) ;2

(c) A ;2 (d) 12

140. !f calCOOC 29EI22 +→+

calOHOH ;9HD2

1222 +→+

calOHCOOCH D921022 222I ++→+

Then the possible heat of methane 'ill be

(a) IF9; cal (b) 2090 cal

(c) I59E cal (d) A IF9; cal

141. Heat of neutrali/ation of strong acid and 'ea,base is

(a) 1195F −mol!

(b) 1F91; −mol!

(c) ess than 1F91; −molcal

(d) ore than 1F91; −molcal

142. system is changed from state * to state ) by

one path and from ) to * another path9 !f 1E and

2E are the corresponding changes in internal

energy& then

(a) ,eEE −=+ 21 (b) ,eEE +=+ 21

(c) 021 =+ EE (d) *one of these

143. The heat evolved during the combination of 2I g Cand 12D g S follo'ing the change is

calHCSSC 0922=22 =∆→+

(a) 11 cal (b) ;2 cal

(c) II cal (d) 22 cal

144. .hen the aueous solution of 095 mole ;HNO is

mi"ed 'ith the 09; mole of −OH solution& then'hat 'ill be the liberated heat ($nthalpy of neutrali/ation is K 5F91 !)

(a) 2D95 ! (b) 1F91 !

(c) I59F ! (d) 19F !

(e) 29D5 !

145. cylinder of gas is assumed to contain 1192 g of

butane )( 10IHC 9 !f a normal family needs 20000

! of energy per day9 The cylinder 'ill lastB (Jiven

that H∆ for combustion of butane is A 25D !)(a) 20 days (b) 25 days

(c) 2 days (d) 2I days

146. Compounds 'ith high heat of formation are lessstable because

(a) High temperature is reuired to synthesisethem

(b) olecules of such compounds are distorted(c) !t is dicult to synthesis them

(d) $nergy rich state leads to instability

147. The heat evolved in the combustion of methane isgiven by the follo'ing euationsB

)=()()(2)( 222I lOHgCOgOgCH +→+

!H ;9DE0−=∆

Ho' many grams of methane 'ould be reuired toproduce II5915 ! of heat of combustion

[AMU 2002]

(a) I g (b) D g

(c) 12 g (d) 1 g

148. Heats of combustion )( oH∆ for )()&( 2 gH'Cand )(I gCH are HD&EI −− and

921; molcal− respectively9 The value of

oH∆ for the reaction&

)()(2)( I2 gCHgH'C →+ is

(a) A D5 cal (b) A 111 cal

(c) A 1F cal (d) A 1F0 cal

149. !f the value of H∆ in a reaction is positive& thenthe reaction is called

(a) $"othermic (b) $ndothermic

(c) -olymorphic (d) -olytropic150. $nthalpy of neutralisation of OHNHI and HCl &

is numerically

(a) 1195F −mol! (b) 1195F −< mol!

(c) 1195F −> mol! (d) ero

151. The heat of neutralisation 'ill be highest in

(a) OHNHI and COOHCH;

(b) OHNHI and HCl

(c) KOH and COOHCH;

(d) KOH and HCl


19/27


152. !f a mole of 2H molecule is heated to high

temperature the follo'ing reaction ta,es place

(a) )()(I;H)(2 gHgH!gH +=+

(b) )(2D20)( 22 gH!gH =+

(c) 22 2I;H)(2 H !gH =+

(d) ++ +=+ HHHH 22

153. .hich of the follo'ing reactions is not e"othermic

(a) )()()( 22 gCOgO'C →+

(b) )()(2)( 2 gCS'S'C →+

(c) )(2)()(2)( 222I lOHgCOgOgCH +→+

(d) )()(2

1)( 22 gCOgOgCO →+

154. 8n combustion& carbon forms t'o o"ides CO and

2CO & Heat of formation of 2CO gas is EI9; cal

and that of CO is 290 cal9 Heat of combustion of carbon is

(a) 290 cal (b) A EI9; cal

(c) D9; cal (d) A 1209; cal

155. 1 mole of conc9 HCl reuires % moles of diluteNaOH for neutralisation and 1 mole of concentrate

I2SOH reuires 6 mole' of small dilute NaOHthen 'hich of the follo'ing reaction is true

(a) % 6 2

1= (b) 6 %

2

1=

(c) 6 % 2= (d) *one of these

156. .hich of the reaction deneso3 H∆

(a) )()( 22)diamond( gCOgOC →+

(b) )()(2

1)(

2

122 gH5 g5 gH →+

(c) )(2)(;)( ;22 gNHgHgN →+

(d) )()(2

1)( 22 gCOgOgCO →+

157. 8ne gram sample of ;INONH is decomposed in

a bomb calorimeter9 The temperature of thecalorimeter increases by 912 K the heat capacityof the system is 192; !gdeg. .hat is the molar

heat of decomposition for ;INONH

(a) A F95; !mol (b) A ;ED91 !mol

(c) A 191 !mol (d) A 02 !mol

158. #or 'hich one of the follo'ing euations isoH react∆ eual to

o3 H∆ for the product

(a) )(2)()(2 22 gCOgOgCO →+

(b) )()()( ;2;2 gONgOgN →+

(c)

)(2)()(2)( 222I gHCllClCHgClgCH +→+

(d) )()(2)( I2 g %e5 g5 g %e →+

159. $nthalpy change for a reaction does not depend

upon (a) The physical states of reactants and products

(b) se of di+erent reactants for the same product

(c) The nature of intermediate reaction steps

(d) The di+erences in initial or nal temperaturesof involved substances

160. diaC N =22 COO → mole!H ;9;E5−=∆

mole!HCOOCgr I9;E;=22 −=∆→+

=∆→ HCCgr =dia

(a) A ;9D (b) A 19E

(c) N ;9D (d) N 19E161. .hat is the 'eight of o"ygen that is reuired for

the complete combustion of 29D g of ethylene:

(a) E9 g (b) E90 g

(c) 9I g (d) 29D g

162. #or complete neutrali/ation of HCl 'ith&NaOH the heat of neutrali/ation is

(a) 1F091; −+ mol! (b) 1F091; −− mol!

(c) 1;295F −− mol! (d) 1;295F −+ mol!

163. The heat of combustion of carbon to 2CO is

mol! 59;E;− 9 The heat released uponformation of ;592 g of 2CO from carbon and

o"ygen gas

(a) !;15+ (b) !59;1−

(c) !;15− (d) !59;1+

164. .hich of the follo'ing euations correctlyrepresents the standard heat of formation

)( o3 H∆ of methane

(a) C (diamond) )(I)(I gg CHH →+

(b) C (diamond) )(I)(22 gg CHH →+

(c) C (graphite) )(I)(22 gg CHH →+

(d) C (graphite) )(I)(I gg CHH →+

165. !f the heat of formation of 2CO is !;E;− 9 The

amount of heat evolved in the formation of 0915

,g of 2CO is

(a) !E91;5F− (b) !E912F5−

(c) !0915F2− (d) !5911H5−

166. .hich of the follo'ing pairs has heat of neutralisation eual to 1;9F Gcals

(a) OHNHHCl I& (b) KOHHNO &;


20/27


(c) COOHCHNaOH ;& (d)

OHNHSOH II2 &

167. The enthalpies of combustion of carbon andcarbon monodie are A;E;95 and A2D; ! molA1

respectivley9 The enthalpy of formation of carbon

mono"ide per mole is

(a) !59HFH− (b) !59HFH

(c) !59110 (d) !59110−

168. The enthalpy of combustion of methane at Co25is !DE0 9 The heat liberated 'hen g29; of

methane is burnt in air is

(a) !II5 (b) !2FD

(c) !DE0− (d) !1FD

169. !f ( i) 22 COOC →+ & ( ii) COOC →+ 221 & (iii)

2221 COOCO →+ & the heats of reaction are

10&12& −−Q respectively9 Then =Q

(a) A 2 (b) 2

(c) A 22 (d) A 1

170. Ho' much energy is released 'hen mole of

octane is burnt in air : Jiveno3 H∆ for

)()&( 22 gOHgCO and )(1DD lHC respectively

are A IE0&A 2I0 and N 10 !0mol

(a) A 92 ! (b) A ;F9I !

(c) A ;595 ! (d) A 2090 !

171. Jiven B !HO5eO5e I91E;&2

;2 ;22 −=∆→+ =

!H2gOO2g 291I0&2

12 −=∆→+

.hat is the H∆ of the reaction

5e2gOO5e2g 2;;2 +→+

(a) A 1D02 ! (b) N1D02 !

(c) A D00 ! (d) N 22D !

172. The enthalpy change )( H∆ for the neutralisation

of HCl21 by caustic potash in dilute solution

at K 2ED is

(a) D ! (b) 5 !

(c) 5F9; ! (d) 50 !

Bond energy

1. !f the bond dissociation energies of 2& % %6 and

26 (all diatomic molecules) are in the ratio of 1 B

1 B 095 and H3 ∆ for the formation of %6 is1200 −− mole! 9 The bond dissociation energy

of 2 % 'ill be

(a) 1100 −mol! (b) 1D00 −mol!

(c) 1;00 −mol! (d) 1I00 −mol!

2. $nergy reuired to dissociate I gm of gaseoushydrogen into free gaseous atoms is 20D ,cal at

Co25 9 The bond energy of HH − bond 'ill be

(a) 10I cal (b) 109I cal

(c) 10I0 cal (d) 10I cal

3. The bond dissociation energy needed to formben/yl radical from toluene is 99999 than theformation of the methyl radical from methane

(a) ess (b) uch

(c) $ual (d) *one of the above

4. .hich one of the follo'ing bonds has the highestaverage bond energy (calmol)

(a) OS = (b) CC ≡

(c) NC ≡ (d) NN ≡5. The bond dissociation energies of gaseous

22&ClH and HCl are 10I& 5D and 10; cal

respectively9 The enthalpy of formation of HClgas 'ould be

(a) A II cal (b) II cal

(c) A 22 cal (d) 22 cal

6. The rst ioni/ation energy for &/ is 59I eV and

electron anity of Cl is ;91eV 9 The H∆ (in

!0mol) for the reaction −+ +→+ Cl&/gClg&/ )()(

is (if resulting ions do not combine 'ith each other)

)10H911( 1E !eV −×=

(a) F0 (b) 100

(c) 1F0 (d) 2F0

7. Jiven that

!HgCHgHgC 1HH)=()(I)( I −=∆→+

The bond energy HC − 'ill be

(a) 20D !mole

(b) A I19 !mole

(c) D;2 !mole

(d) *one of these

8. The HH − bond energy is I;0 ! moland

ClCl − bond energy is Hmol! ∆−92I0

1 for

HCl is !E0− 9 The ClH − bond energy isabout

(a) 11D0 −mol! (b) 1;H0 −mol!

(c) 121; −mol! (d) 1I25 −mol!

9. !f enthalpies of methane and ethane arerespectively ;20 and ;0 calories then the bond

energy of CC− bond is

(a) D0 calor/e' (b) I0 calor/e'

(c) 0 calor/e' (d) 120 calor/e'

10. !f the bond energies of HH − & )r )r − and

H)r are I;;& 1E2 and ;I 1−mol!

respectively& the o

H∆ for the reaction&

)(2)()( 22 gH)r g)r gH →+ is


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(a) N 21 ! (b) A 10; !

(c) A 21 ! (d) N 10; !

Free energy and Work function

1. The free energy change for a reversible reaction ateuilibrium is

(a) arge positive (b) 3mall negative

(c) 3mall positive (d) 0

2. #or a spontaneous change& free energy change

G∆ is(a) -ositive

(b) *egative

(c) ero

(d) Can be positive or negative

3. minus sign of the free energy change denotesthat

(a) The reaction tends to proceed spontaneously

(b) The reaction is nonLspontaneous(c) The system is in euilibrium

(d) The reaction is very much unli,ely

4. The relation bet'een G∆ and H∆ is

(a) ST GH ∆−∆=∆ (b) ST HG ∆−∆=∆

(c) HGST ∆=∆−∆ (d) SGT H ∆+∆=∆

5. t ;00 K & the reactions 'hich have follo'ingvalues of thermodynamic parameters occurspontaneously

(a) 1I00 −−=∆ mol!Go

(b)111

I&200 −−−

−=∆=∆ mol !K Smol!Hoo

(c)111 I&200 −−− =∆−=∆ mol !K Smol!H oo

(d) 111 I0&200 −−− =∆=∆ mol !K Smol !H oo

6. The relation ST HG ∆−∆=∆ 'as given by

(a) 4olt/mann (b) #araday

(c) JibbsAHelmholt/ (d) Thomson

7. #or precipitation reaction of + *g ions 'ith

NaCl & 'hich of the follo'ing statements iscorrect

(a) H∆ for the reaction is /ero(b) G∆ for the reaction is /ero

(c) G∆ for the reaction is negative

(d) RSRS HG ∆=∆

8. t constant pressure and temperature& thedirection to the result of any chemical reaction is'here& there is less amount of

(a) $ntropy (b) $nthalpy

(c) Jibb%s free energy (d) *one of the above

9. The dependence of Jibbs free energy on pressurefor an isothermal process of an ideal gas is given

by

(a)1

2lnP

PnRT GT =∆ (b)

1

2lnV

V nRT GT =∆

(c)2

1logP

PnRT GT =∆ (d)

1

2logV

V nRT GT =∆

10. #or the change atmPgOHlOH 1)=()( 22 =→ &

K T ;F;= & the free energy change 0=∆G 9 This indicates that

(a) )(2 lOH is in euilibrium 'ith )(2 gOH

(b) .ater boils spontaneously at K ;F;

(c) .ater does not boil spontaneously at K ;F;

(d) Condensation of 'ater vapour occurs

spontaneously at K ;F;

11. .hat is the free energy change G∆ 'henmole091 of 'ater at Co100 and at 1

pressure is converted into steam at Co100 and

at 1 pressure

(a) cal5I0 (b) calED00−

(c) calED00 (d) cal0

12. oG∆ for the reaction 6 % +


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(c) HTSG =− (d) HSG ==

18. The essential condition for the feasibility of areaction is that

(a) The reaction should be e"othermic

(b) The entropy of products must be larger than

that of reactants(c) The reaction is to be accompanied 'ith free

energy decrease

(d) The reaction has to possess high activationenergy

19. The correct relationship bet'een free energychange in a reaction and the corresponding

euilibrium constant cK is

(a) cK RT G ln=∆ (b) cK RT G ln=∆−

(c) co K RT G ln=∆ (d) c

o K RT G ln=∆−

20. !n an irreversible process ta,ing place at constant

T and P and in 'hich only pressureLvolume 'or, isbeing done& the change in Jibbs free energy

)(dG and change in entropy )(dS & satisfy thecriteria

(a) 0)(&0)( && = PT EV dGdS

21. The densities of graphite and diamond at 2ED K are2925 and ;9;1 g cmA;& respectively9 !f the standard

free energy di+erence )(o

G∆ is eual to 1DE5 !1−mol & the pressure at 'hich graphite 'ill be

transformed diamond at 2ED K is

(a) Pa510E29E × (b) PaD10E29E ×

(c) PaF10E29E × (d) PaH10E29E ×

22. The free energy change for the follo'ing reactionsare given belo'&

→+ )(2

5)( 222 gOgHC

!GlOHgCO o 12;I)=()(2 22 −=∆+

!GgCOgO'C o ;EI)()()( 22 −=∆→+

!GlOHgOgH o 2;F)()(2

1)( 222 −=∆→+

.hat is the standard free energy change for the

reaction )()()( 222 gHC'CgH →+ 2

(a) A 20E ! (b) A 225E !

(c) N 225E ! (d) 20E !

23. The euilibrium concentration of the species in the

reaction (C) * +≡+ are ;& 5& 10 and 151−&mole respectively at K ;00 the

G∆ for

the reaction is

(a) 1;9D1 (b) A 1;D19D

(c) A 1;D91D (d) 1;E19

24. JibbPs free enrgy )(G is dened as

(a) ST HG ∆−∆=∆ (b)

S

T HG

∆

+∆=∆

(c) ST GH ∆−∆=∆ (d) -CT HG 9+∆=∆

25. 3tandard enthalpy and standard entropy changes

for the o"idation of ammonia at K 2ED are1

HI9;D2 −

− mol! and 11H91I5 −−− mol !K &

respectively9 3tandard Jibbs energy change for

the same reaction at K 2ED is

(a) A I;E9; ,@ 1−mol (b) A 52;921−mol!

(c) A 22191 1−mol! (d) A ;;E9; 1−mol!

26. #or spontaneity of a cell& 'hich is correct

(a) 0&0 =∆=∆ EG

(b) 0& =∆−=∆ EeG

(c) eEeG +=∆+=∆ &

(d) eEeG +=∆−=∆ &

27. The free energy for a reaction having

=;1I00caH =∆ 9 11;2 −−=∆ molK calS at

Co1000 is

(a) A E;; cal (b) A F;D cal

(c) A1E; cal (d) N E;; cal

28. The H

∆ and S

∆ for a reaction at oneatmospheric pressure are N;0955D ! and

10HH90

−! respectively9 The temperature at

'hich the free energy change 'ill be /ero andbelo' of this temperature the nature of reaction'ould be

(a) ID; K & spontaneous

(b) II; K & nonLspontaneous

(c) II; K & spontaneous

(d) I; K & nonLspontaneous

(e) I; K & spontaneous

1. dsorption of gases on solid surface is generallye"othermic because

(a) $nthalpy is positive (b) $ntropy decreases

(c) $ntropy increases (d) #ree energy increase

2. T'o mole of an ideal gas is e"panded isothermally

and reversibly from 1 litre ot 10 litre at K ;00 9

The enthalpy change (in ! ) for the process is

(a) 119I ! (b) A119I !


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(c) 0 ! (d) I9D !

3. Heat of neutrali/ation of strong acid against strongbase is constant and is eual to

(a) 1;9F cal (b) 5F !

(c) I10F95 × ! (d) ll of the above

4. The value of heat generated 'hen ;95 gm HCland I0 gm of NaOH reacts during neutrali/ation

(a) F95 cal (b) 1;9F cal

(c) ore than 1;9F cal (d) 10D ,cal

5. .hen a gas undergoes adiabatic e"pansion& it getscooled due to

(a) oos of ,inetic energy

(b) #all in temperature

(c) 7ecrease in velocity

(d) $nergy used in doing 'or,

6. The heat content of a system is called

(a) !nternal energy (b) $ntropy

(c) #ree energy (d) $nthalpy

7. To calculate the amount of 'or, done in Voulesduring reversible isothermal e"pansion of an idealgas& the volume must be e"pressed in

(a) ;m only (b) ;dm only

(c) ;cm only (d) ny one of them

8. !n an isobaric process& the ratio of heat supplied to

the system )(dQ and 'or, done by the system

)(dW for diatomic gas is

(a) 1 B 1 (b) F B 2(c) F B 5 (d) 5 B F

9. The enthalpy change for the reaction of 50900 ml

of ethylene 'ith 50900 ml of 2H at 195 atm

pressure is !H ;190−=∆ 9 The value of E∆'ill be

(a) A09;02I ! (b) 09;02I !

(c) 295F ! (d) A0900F !

10. $nthalpy of solution of NaOH (solid) in 'ater is1

H9I1 −

− mol! 9 .hen NaOH is dissolved in'ater& the temperature of 'ater

(a) !ncrease (b) 7ecreases(c) 7oes not change (d) #luctuatesindenitely

11. !n 'hich of the follo'ing entropy decreases :

(a) Crystalli/ation of sucrose from solution

(b) usting of iron

(c) elting of ice

(d) 6apori/ation of camphor

12. #or conversion C (graphite) → C (diamond) the

S∆ is

(a) ero (b) -ositive

(c) *egative (d) n,no'n

13. #or a reaction 10D9E −=∆ mol!H and

11F9;5 −−=∆ mol !K S

.hich of the follo'ing statements is correct forthe reaction

(a) eversible and !sothermal

(b) eversible and $"othermic

(c) 3pontaneous and $ndothermic

(d) 3pontaneous and $"othermic

14. #or a reaction to occur spontaneously

(a) )( ST H ∆−∆ must be negative

(b) )( ST H ∆+∆ must be negative

(c) H∆ must be negative

(d) S∆ must be negative

15. The total amount of energy in the universe is"ed& but

(a) 7isorder is increasing (b) ightning is

increasing(c) atter is increasing (d) Jravitation isdecreasing

16. !f for a given substance melting point is )T and

free/ing point is *T & then correct variation

sho'n by graph bet'een entropy change andtemperature is

(a) (b)

(c) (d)

17. !n endothermic reaction& the value of change in

enthalpy )( H∆ is

(a) -ositive (b) *egative

(c) ero (d) *one of these

18. .hich of the follo'ing 'ould be e"pected to havethe largest antropy per mole

(a) )(22

'ClSO (b) )(22

gClSO

(c) )(22 lClSO (d) )(2 gSO

19. The enthalpies of formation of ;2O *l and

;2OCr are !15EH− and !11;I−

respectively9 H∆ for the reaction

;2;2 22 O *lCr OCr *l +→+ is

(a) !2F;0− (b) !IH2−

(c) !1;H5− (d) !2F;0+

20. Heat of reaction at constant volume is measuredin the apparatus

(a) 4omb calorimeter (b) Calorimeter(c) -y,nometer (d) -yrometer

T

∆ST

4

T

T

∆S

T 4

T

T

∆ST

4T

T

∆S T 4T


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181 Thermodynamics and Thermochemistry21. .hich of the follo'ing gas has the highest heat of

combustion

(a) ethane (b) $thane

(c) $thylene (d) cetylene

22. The amount of heat measured for a reaction in a

bomb calorimeter is(a) G∆ (b) H∆

(c) E∆ (d) V P∆

23. #or an endothermic reaction 'here H∆represents the enthalpy of the reaction in !0mole&the minimum value for the energy of activation'ill be

(a) ess than H∆ (b) ero

(c) ore than H∆ (d) $ual to H∆24. The heat of neutrali/ation of a strong acid by a

strong base is nearly eual to

(a) N 5F9;2 ! (b) A 5F9;2 !

(c) N 1;9F ! (d) A 1;9F !

25. 4ec,mann thermometer is used to measure

(a) High temperature (b) o' temperature

(c) *ormal temperature (d) ll temperature

26. The heat reuired to raise the temperature of abody by 1 K is called

(a) 3pecic heat (b) Thermal capacity

(c) .ater euivalent (d) *one of these

27. echanical 'or, is specially important in systemthat contain

(a) 3olidLliuid (b) iuidLliuid

(c) 3olidLsolid (d) malgam(e) Jases

28. >The uantity of heat 'hich must be supplied todecompose a compound into its element is eualto the heat evolved during the formation of thatcompound from the elements9? This statement is,no'n as

(a) Hess%s la'

(b) @oule%s la'

(c) eAchatelier%s principle

(d) avoiser and aplace la'

29. Hess la' deals 'ith

(a) Changes in heat of reaction(b) ate of reaction

(c) $uilibrium constant

(d) !nQuence of pressure on volume of a gas

30. #or 'hich one of the follo'ing reactions& H∆ isnot eual to E∆

(a) )(2)(2 gg IH + < )(2 gHI

(b) )(2)( g' OC + < )(2 gCO

(c) )(2)(2 ; gg HN + < )(;2 gNH

(d) )()( aqaq NaOHHCl + < OHNaClaq 2)( +

31. The heat liberated 'hen 19DE g of ben/oic acid is

burnt in a bomb calorimeter at Co25 increases

the temperature of 1D9EI g of 'ater by

CoH;290 9!f the specic heat of 'ater at Co25is 09EED calg

02 Chep Thermodynamics and Thermochemisty Ques. Final E

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Transcript of 02 Chep Thermodynamics and Thermochemisty Ques. Final E