Acid and Base

Ch 15 and 16

acids• 1. tastes sour.• 2. conducts an electric current.• 3. Causes certain dyes ( indicators) to change

color.• 4. Liberates hydrogen when it reacts with certain

metals.• 5. neutralizes basic solutions to form salts.

Bases

• 1. tastes bitter.• 2. conducts an electric current.• 3. causes certain dyes ( indicators) to change

color.• 4. feels slippery.• 5. neutralizes acid solution to form salts.

Definition of Acids and Bases

• An acid is a source of hydrogen ions (H+) or hydronium ions (H3O+ ) in solution.

HCl(aq) + H2O(l) H3O+ (aq) + Cl- (aq)

• A base is a source of hydroxide ions (OH-)

e.g. NaOH(s) Na+ (aq) + OH- (aq)

e.g. NH3 (aq) +H2O(l) NH4+ (aq) + OH-

(aq)

Naming of acids

1. In a binary acid, the negative anion ends in -ide. The name begins with the prefix hydro- , stem and ends with -ic acid.

hydro______ ic acidHFHClHBr

hydroflouric acid

hydrochloric acid

Hydrobromic acid

stemstem

2. In an oxy acid, the negative anion ends in –ate, use the stem and the name ends with -ic acid.

______ ic acid

HNO3

H2SO4

H3PO4

CH3COOH

nitric acid

phosphoric acid

sulfuric acid

acetic acid

3. In an oxy acid, if the negative anion ends in –ite, use the stem and the name ends with -ous acid.

_______ ous acid

HNO2

H2SO3

H3PO3

nitrous acid

sulfurous acid

phosphorous acid

Some Common Bases

NaOH

KOH

Ba(OH)2

Mg(OH)2

Al(OH)3

Sodium hydroxide

Potassium hydroxide

Barium hydroxide

Magnesium hydroxide

Aluminum hydroxide

Learning Check

Match the formulas with the names:

A. ___ HNO2 1) hydrochloric acid

B. ___ Ca(OH)2 2) sulfuric acid

C. ___ H2SO4 3) sodium hydroxide

D. ___ HCl 4) nitrous acid

E. ___ NaOH 5) calcium hydroxide

Solution AB4

Match the formulas with the names:

A. _4__ HNO2 1) hydrochloric acid

B. _5__ Ca(OH)2 2) sulfuric acid

C. _2__ H2SO4 3) sodium hydroxide

D. _1__ HCl 4) nitrous acid

E. _3__ NaOH 5) calcium hydroxide

Learning Check

Acid, Base Nameor Salt

CaCl2 ______ _________________

KOH ______ _________________

Ba(OH)2 ______ _________________

HBr ______ _________________

H2SO4 ______ __________________

Solution AB5

Acid, Base Nameor Salt

CaCl2 salt calcium chloride

KOH base potassiuim hydroxide

Ba(OH)2 base barium hydroxide

HBr acid hydrobromic acid

H2SO4 acid sulfuric acid

B. DefinitionsB. Definitions• ArrheniusArrhenius - In aqueous solution… - In aqueous solution…

HCl + H2O H3O+ + Cl–

– AcidsAcids form hydronium ions (H3O+)

H

HH H H

H

ClClO O

–+

acid

B. DefinitionsB. Definitions• ArrheniusArrhenius - In aqueous solution… - In aqueous solution…

– BasesBases form hydroxide ions (OH-)

NH3 + H2O NH4+ + OH-

H

H

HH H

H

N NO O–+

H

H

H H

base

B. DefinitionsB. Definitions• Brønsted-LowryBrønsted-Lowry

HCl + H2O H3O+ + Cl-

– AcidsAcids are proton (H+) donors. – BasesBases are proton (H+) acceptors.

conjugate base

conjugate acid

baseacid

Conjugate acid base pairs

• conjugate base: the species that remains after an acid has given up a proton

• conjugate acid: the species that is formed when a base gains a proton

NH3 + H2O NH4+ + OH-

conjugate base

conjugate acid

acidbase

• In the two examples water first acts as a base, then as an acid.

• Any species which can both accept and receive protons is called amphiprotic. (also known as amphoteric)

Br –

HSO4-

CO32-

HBr

H2SO4

HCO3-

• Give the conjugate acid for each of the following:

• List the conjugate acids for the following Bronsted bases

• OH -

• CO3 2-

• NO3-

• HCO3-

• CN -

H2O

HCO3-

HNO3

HCO3

HCN

F -

H2PO4-

H2O

HF

H3PO4

H3O+

• Give the conjugate base for each of the following:

• Polyprotic - an acid with more than one H - an acid with more than one H++

• List the conjugate bases for the following Bronsted acids

• H2SO4

• HPO42-

• HCO3-

• H3O+

• H2PO4-

HSO4-

PO43-

CO32-

H2O

HPO42-

Review 2: Name the acid, base, conjugate acid and base for each reaction.

CH3NH2 + H2O CH3NH3+ + OH -

H3PO4 + H2O H3O + + H2PO4 -

HC2H3O2 + H2O H3O + + C2H3O2 -

CH3NH3+ + H2PO4 - H3PO4 + CH3NH2

base

base

base

base

acid

acid

acid

acid

conjugate acid

conjugate acid

conjugate acid

conjugate acid

conjugate base

conjugate base

conjugate base

conjugate base

Review 2: Name the acid, base, conjugate acid and base for each reaction.

H2PO42- + OH- HPO4

- + H2O

HCN + H2O CN- + H3O +

NH3 + H2O NH4 + + OH -

NO3- + HCO3 - CO3

2- + HNO2

acid

base

acid

acid

base

acid

base

base

conjugate base

conjugate base

conjugate acid

conjugate base

conjugate acid

conjugate acid

conjugate base

conjugate acid