1 Brnsted-Lowry 2 3 1 2 3 1 2 pH3

1.

Brnsted-Lowry H+ H+

NH4+ NH3 + H+[Al(H2O)6]3+ [Al(H2O)5(OH)]2+ + H+HCO3 CO32 + H+

+ H+

2. H+ +

HCl H+ + Cl

HCl + H2O H3O+ + Cl 1 2 2 1

NH4+ + H2O H3O+ + NH3 1 2 2 1

H+H+H+

2.

Ac + H2O HAc + OH 1 2 1 2

H+

3. 1 2 HAc Ka (-396.6 -237.19 -237.19 -369.4 (kJ/mol)

Ka

H3O+(aq) + H2O (l) H3O+ (aq) +H2O (l) K = 1

H2O + H2O H3O+ + OH 25 C [H3O+] = [OH] = 1.0 107 mol/dm3)

Kw = [H3O+] [OH] = 1.0 1014 ( Kw Kw

Kw

H2O(l) + H2O(l) H3O+(aq) + OH(aq) -237.2 -237.2 -237.2 -157.3 (kJ/mol) = 79.90

[H3O+] = [OH] = 1.0 107 mol/dm3) pH = - lg [H3O+] = 7 = pOH

0.10 mol/dm3 [OH] = Kw / [H3O+] = 1.0 1014 / 1.0 101 = 1.0 1013mol/dm3)0.10 mol/dm3 [H3O+] = Kw / [OH] = 1.0 1014 / 1.0 101 = 1.0 1013mol/dm3) ( H3O+ OH KwOH H3O+

10.10 mol/dm3 HAc Ka = 1.76 105 HAc + H2O H3O+ + Ac 0.10-x x x H3O+ x Ka = [H3O+] [Ac] / [HAc] = x2 / (0.10-x) x2 / 0.10 = 1.76 105 x = [H3O+] = (0.10 1.76 105 )0.5 = 1.3 103 (mol/dm3 ) = x / C0 = 1.3 103 / 0.10 = 0.013 (1.3%)

[H3O+ ] [OH]) 1 0.10 mol/dm3 HA H2O H3O+ [H3O+ ] < 10-7 (mol/dm3) 2 HA 5% c/K 380 400 c HAK

[H3O+ ] [OH])

2.45NaCN500 cm3HCNKa 4.931010CN 2.45/(49.0 0.500)=0.100 (mol/dm3) CN + H2O OH + HCN

= Kw/Ka = 1.00 1014/ 4.93 1010 = 2.03 105 c/Kb = 0.100/2.03 105 = 4.93 103 > 400 [OH] = Kbc)0.5 = (2.03 105 0.100)0.5 = 1.42 103 (mol/dm3) pH = 14.0 pOH = 14.0 2.85 = 11.15

2 H2S H2S + H2O H3O+ + HS Ka1 = [H3O+] [HS] / [H2S] = 9.1 108 HS + H2O H3O+ + S2 Ka2 = [H3O+] [S2] / [HS] = 1.1 1012

Ka1 Ka2

1 H2S + H2O H3O+ + HS 0.1-x x+y x-y

HS + H2O H3O+ + S2 x-y x+y y Ka1 = [H3O+] [HS] / [H2S] = 9.1 108

Ka2 = [H3O+] [S2] / [HS] = 1.1 1012

Ka1 >> Ka2 c / Ka1 = 0.1/ 9.1 108 >> 400 [H3O+] x+y x 9.1 108 0.1 )0.5 = 9.5 105 mol/dm3 pH = 4.02 0.10 mol/dm3 H2S [H3O+] [S2]H2S

1 H2S + H2O H3O+ + HS 0.10-x x+y x-y

HS + H2O H3O+ + S2 x-y x+y y [S2] = Ka2 ([HS] / [H3O+] ) = Ka2 (x-y / x+y )

x >> y [HS] [H3O+] [S2] Ka2 = 1.1 1012 mol/dm3

H2S = x / c = 9.5 105 / 0.10 = 9.5 104 0.1%)

H2S0.10 mol/dm3 H2S [H3O+] [S2]H2S

2 S2 + H2O OH + HS

HS + H2O OH + H2S

Kb1 = Kw/Ka2 = 1.0 1014 / 1.1 1012 = 9.1 103

Kb2 = Kw/Ka1 = 1.0 1014 / 9.1 108 = 1.1 107 Kb1 >> Kb2 0.10 mol/dm3 Na2S [S2] [OH] , S2

2 S2 + H2O OH + HS 0.10 x x x

c / Kb1 = 0.10/ 9.1 103 = 11 < 400

x = [OH] = 2.5 102 mol/dm3 [S2] = 0.10 x = 0.10 0.025 = 7.5 102 mol/dm3 S2 = x / c = 0.025 / 0.10 = 0.25 25%)

0.10 mol/dm3 Na2S [S2] [OH] , S2

3 H2PO4 + H2O H3O+ + HPO42

Ka2(H3PO4) = 6.23 108

H2PO4 + H2O OH + H3PO4

Ka2 >> Kb3

NaH2PO4 H+H+

1. [H3O+] [H3O+] 2. H2A [A2] Ka23. Na2S, Na2CO3, Na3PO4KbKa 4. H2PO4, HCO3 pH

Ka Ka [H3O+]

NH4+ + Ac + H2O NH3H2O + HAc 0.10 x 0.10 x x x

K x 0.10 x 0.10

x2 / 0.102 = 3.1105

x = [NH3] = [HAc] = (3.1 107)0.5 = 5.6 104 (mol/dm3) 0.10 mol/dm3 NH4Ac pH

NH4+ + Ac + H2O NH3H2O + HAc 0.10 x 0.10 x x x

HAc + H2O H3O + Ac x y 0.10 x

pH = 7.00 0.10 mol/dm3 NH4Ac pH

NH4+ + Ac + H2O NH3H2O + HAc 0.10 x 0.10 x x x

0.010M H2SO4(aq)25CpH?(H2SO4 Ka1 Ka2 = 1.210-2)

1NH3 H2O + NH4Cl(s)

NH3 + H2O OH + NH4+ NH4+ NH3

2HAc + NaAc(s)

HAc + H2O H3O+ + Ac Ac HAc

pH pH

1pH 1 HAc + H2O H3O+ + Ac [H3O+] > Ka pH < pKa [Ac-]/[HAc] < 1, HAc [H3O+] = Ka pH = pKa [Ac-]/[HAc] = 1, Ac HAc [H3O+] < Ka pH > pKa [Ac-]/[HAc] > 1, Ac

2 HIn) HIn + H2O H3O+ + In [H3O+] [In] > [HAc], KHIn pKHIN 1

pKHInpH (18C) ()3.43.1 4.4H2In)In2 1.65 (pK, H2In)9.20 (pK,HIn )1.2 2.88.0 9.69.18.2 10.0

3 H2SpHS2- H2S + H2O H3O+ + HS HS + H2O H3O+ + S2 [H3O+] > Ka1 , ([HS] / [H2S]) < 1 , H2S Ka1 > [H3O+] > Ka2 , HS [H3O+] < Ka2 , ([S2] / [HS] ) > 1 , S2 H2S + 2H2O 2H3O+ + S2 pH < 5H2S: [H2S] C(H2S )= 0.10 (mol/dm3) [H3O+ ][S2] = Ka1 Ka2 C(H2S ) = 1.0 10 20 (

(1)HS-2[S2]1/2[H3O+] H2S + 2H2O 2H3O+ + S2 0.30 mol/dm3 HCl H2S [H2S] 0.10 mol/dm3 S2[H3O+ ][S2] = Ka1 Ka2 C(H2S ) = 1.0 10 20 ( [S2]= 1.0 10 20 /(0.30)2 = 1.1 10 19 (mol/dm3)

H2S 0.10 mol/dm3 [S2]= Ka2 = 1.1 10 12 (mol/dm3)

10 7 S2

2pH 0.10 mol/dm3 HAc 0.10 mol/dm3 NaAcpHHAc HAc + H2O H3O+ + Ac 0.10 0.10 0.10 x x 0.10 + x HAc [HAc] CHAc = 0.10 mol/dm3 , [Ac] CAc- = 0.10 mol/dm3 x = [H3O+] = Ka CHAc/ CAc-) = 1.8 105 pH = 4.74 2.88, NaAc = 1.8 105 /0.10 = 1.8 104 (0.018 %)

1 + 2 NaOH(aq) 12

HCl (aq) 34 2 HAc NaAc + 2 NaOH(aq) 4

HCl (aq) 4 pH

HAc + H2O H3O+ + Ac (1) 1:1 CHAc CAc- 1.0 mol/dm3 pH = pKa 0.01 molH3O+ pH = pKa + lg(1.0 - 0.01)/(1.0 + 0.01) pKa 0.01, pH 0.01 CHAc=1.98, CAc- = 0.02 (mol/dm3), pH = pKa+ lg(0.02)/(1.98) ( 99:1 ) pKa 2.0 0.01 molH3O+ pH = pKa + lg(0.02 - 0.01)/(1.98 + 0.01) pKa 2.3, pH 0.3 1:10 10:1 pH = pKa 1 pHpKa.

(2) 1:1CHAc CAc- 0.10 mol/dm3 0.01 molH3O+ pH = pKa + lg(0.10 - 0.01)/(0.10 + 0.01) pKa 0.10, pH 0.1 CHAc CAc- 1.0 mol/dm3 0.01 molH3O+ pH 0.01 10 0.1~1.0 mol/dm3 pHpKa.

pKaHCO2H/NaOHHCO2H-HCO23.752.75-4.75CH3CO2H -CH3CO2NaHAc - Ac 4.753.75-5.75NaH2PO4-Na2HPO4H2PO4 HPO427.216.21-8.21NH3H2O -NH4ClNH4+ - NH3 9.258.25-10.25NaHCO3 -Na2CO3HCO3 - CO3210.259.25-11.25Na2HPO4 -NaOHHPO4 2 - PO4312.6611.66-13.66

1 pH=3.20HCO2H - HCO2Na CH3CO2H -CH3CO2Na

pH=3.20 [H3O+] = 6.3 104Ka[H3O+] []/[]= [H3O+] /Ka = 1

: Ka (HCO2H) = 1.77 104, pKa=3.75 Ka (HAc) = 1.76 105, pKa=4.75

HCO2H - HCO2Na [HCO2H]/[HCO2]= 6.3 104 / 1.77 104 = 3.6 / 1 1

CH3CO2H -CH3CO2Na [HAc]/[Ac]= 6.3 104 / 1.76 105 = 36 / 1 1

2 pH=9.20, C(NH3H2O) =1.0 mol/dm3 500 cm3NH3H2O NH4Cl

pH=9.20 pOH = 4.80, [OH] = 1.6 105 mol/dm3 [NH3H2O ]/[NH4+]= [OH] /Kb = 1.6 105/1.77 105 = 0.90

[NH3H2O ] = 1.0 mol/dm3 [NH4Cl] = 1.0 / 0.90 = 1.1 mol/dm3

500 cm30.50 dm3)NH4Cl 0.50 1.1 53.5 = 29 NH3H2O 15 mol/dm3 , V (NH3H2O) = 1.0 500 / 15 = 33 cm3

29NH4Cl33 cm3NH3H2O 500 cm3

3 pH=4.70500 cm350 cm3 1.0 mol/dm3 NaOH cm3 1.0 mol/dm3 HAc

Ka(HAc) = 1.76 105 , pH=4.70[H3O+] = 2.0 105 mol/dm3 [HAc ]/[Ac]= [H3O+] /Ka = 2.0 105/1.76 105 = 1.1

[Ac] NaOH HAc [Ac] = 1.0 50 / 500

[HAc ]NaOH HAc [HAc ] = ( 1.0 VHAc 1.0 50) / 500

[HAc ]/[Ac] = 1.1 = ( 1.0 VHAc 1.0 50) / 1.0 50

VHAc 105 cm3 1.0 102 cm3 500-155 = 345 cm3 3.5 102 cm3

Buffers in the BodypH of human blood: 7.35-7.45 [HCO3-]/[H2CO3] in the blood: 20/1

[HCO3-]/[H2CO3] increases, pH rises: (alkalosis)[HCO3-]/[H2CO3] decreases, pH falls: (acidosis)Reepiration() CO2, [H2CO3] ()Rate of excretion in urine ()[HCO3-] ()

http://jpkc.bjmu.edu.cn/jpkc-sb/bingli%20shenglixue/

H3O+ + OH H2O + H2O

HCl NaAc H3O+ + Ac HAc + H2O

NaOH HAc HAc + OH Ac + H2O

HAc + S2 Ac + HS

H3O+ + A HA + H2O HA HA + OH A + H2O

: 4.3 4.7 4.11 4.16 4.18 4.21 4.22

pH1. pH 5)

Ka1 >> Ka2 ,

2. pH S2

3. pH pH pKa 1/10 10/1; 0.1 1.0 mol/dm3

H3O+ + H2O H3O+ + H2O K = 1