1

Acids and Bases

2

Arrhenius Acids and Bases

Acids produce H+ in aqueous solutions water

HCl H+(aq) + Cl- (aq)

Bases produce OH- in aqueous solutions

water

NaOH Na+(aq) + OH- (aq)

3

Acids

þ Produce H+ (as H3O+) ions in water

þ Produce a negative ion (-) too

þ Taste sour

þ Corrode metals

þ React with bases to form salts and water

4

Bases

Produce OH- ions in water

Taste bitter, chalky

Are electrolytes

Feel soapy, slippery

React with acids to form salts and

water

5

Learning Check AB1

Describe the solution in each of the following as: 1) acid 2) base or 3)neutral.A. ___soda

B. ___soapC. ___coffeeD. ___ wineE. ___ water

F. ___ grapefruit

6

Solution AB1

Describe each solution as: 1) acid 2) base or 3) neutral.A. _1_ soda

B. _2_ soapC. _1_ coffeeD. _1_ wineE. _3_ water

F. _1_ grapefruit

7

Learning Check AB2

Identify each as characteristic of an A) acid or B) base

____ 1. Sour taste

____ 2. Produces OH- in aqueous solutions

____ 3. Chalky taste____ 4. Is an electrolyte____ 5. Produces H+ in aqueous solutions

8

Solution AB2

Identify each as a characteristic of an A) acid or B) base

_A_ 1. Sour taste

_B_ 2. Produces OH- in aqueous solutions

_B_ 3. Chalky taste

A, B 4. Is an electrolyte

_A_ 5. Produces H+ in aqueous solutions

9

Some Common Acids

HCl hydrochloric acid

HNO3 nitric acid

H3PO4 phosphoric acid

H2SO4 sulfuric acid

CH3COOH acetic acid

10

Learning Check AB3

Give the names of the following A. HBr (aq) 1. bromic acid

2. bromous acid

3. hydrobromic acid

B. H2CO3 1. carbonic acid

2. hydrocarbonic acid

3. carbonous acid

11

Solution AB3

A. HBr 3. hydrobromic acidThe name of a nonoxy acid begins with the prefix hydro- and ends with -ic acid. In a nonoxy acid, the negative anion end in -ide.

B. H2CO3 1. carbonic acidThe name of an oxyacid is named with the stem of the anion (carbonate) changed to -ic acid

12

Some Common Bases

NaOH sodium hydroxide

KOH potassium hydroxide

Ba(OH)2 ________________________

Mg(OH)2 ________________________

Al(OH)3 aluminum hydroxide

13

Learning Check AB4

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

14

Solution AB4

Match the formulas with the names:

A. _4__ HNO2 1) hydrochloric acidB. _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

15

Learning Check AB5Learning Check AB5

Acid, Base Nameor Salt

CaCl2 ______ _________________

KOH ______ _________________

Ba(OH)2 ______

_________________

HBr ______ _________________

H2SO4 ______ __________________

16

Solution AB5

Acid, Base Nameor Salt

CaCl2 salt calcium chlorideKOH base potassiuim hydroxideBa(OH)2 base barium hydroxideHBr acid hydrobromic acidH2SO4 acid sulfuric acid

17

Bronsted-Lowry Acids

Acids are hydrogen ion (H+) donorsBases are hydrogen ion (H+) acceptors

HCl + H2O H3O+ + Cl-

donor acceptor + -

+ +

18

pH

Indicates the acidity [H3O+] of the solution

pH = - log [H3O+]

From the French pouvoir hydrogene

(“hydrogen power” or power of hydrogen)

19

In the expression for [H3O+]

1 x 10-exponent

the exponent = pH

[H3O+] = 1 x 10-pH M

pH

20

pH Range

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Neutral

[H+]>[OH-] [H+] = [OH-] [OH-]>[H+]

Acidic Basic

21

Some [H3O+] and pH

[H3O+] pH

1 x 10-5 M 5

1 x 10-9 M 9

1 x 10-11 M 11

22

pH of Some Common Acids

gastric juice 1.0

lemon juice 2.3

vinegar 2.8

orange juice 3.5

coffee 5.0

milk 6.6

23

pH of Some Common Bases

blood 7.4

tears 7.4

seawater 8.4

milk of magnesia 10.6

household ammonia 11.0

24

Learning Check pH4

A. The [H3O+] of tomato juice is 1 x 10-4 M. What is the pH of the solution?1) - 4 2) 4 3) 8

B. The [OH-] of an ammonia solution is

1 x 10-3 M. What is the pH of the

solution?

1) 3 2) 11 3) -11

25

Solution pH4

A. pH = - log [ 1 x 10-4] = -(- 4) = 4

B. [H3O+] = 1 x 10-11

pH = - log [ 1 x 10- 11] = -(- 11) = 11

26

Solution pH5

The pH of a soap is 10. What is the

[H3O+] of the soap solution?

[H3O+] = 1 x 10-pH M

= 1 x 10-10 M

27

Acid RainUnpolluted rain has a pH of 5.6

Rain with a pH below 5.6 is “acid rain“

CO2 in the air forms carbonic acid

CO2 + H2O H2CO3

Adds to H+ of rain

H2CO3 H+ (aq) + HCO3-(aq)

Formation of acid rain:1. Emission of sulfur and nitrogen oxides from the burning of fuels expecially coal with high S content, power stations, oil refineries, vehicles as well

as bacterial decomposition, and lighting hitting N2

SO2 26 million tons in 1980

NO and NO2 22 million tons in 1980

Mt. St Helens (1980) 400,000 tons SO2

2. Reactions in the atmosphere form SO3

2SO2 + O2 ⎯→ 2 SO3

3. Reactions with atmosphere water form acidsSO3 + H2O ⎯→ H2SO4 sulfuric acid

NO + H2O ⎯→ HNO2 nitrous acid

HNO2 + H2O ⎯→ HNO3 nitric acid

4. Effects of Acid RainDecline in fish populations in rivers and lasts due to toxic effect of Al leached from soil by acid rainExtensive fish kills in spring from runoff due to accumulation of large amounts of acid on the snow Dissolves minerals Mg, Ca, and K from the soil and waxy coatings that protect leaves from bacteriaCorrodes metals, textiles, paper and leather

28

Acid Rain continued...Sources of Acid Rain

Power stations

Oil refineries

Coal with high S content

Car and truck emissions

Bacterial decomposition, and lighting

hitting N2

29

SO2 26 million tons in 1980

NO and NO2 22 million tons in 1980Mt. St Helens (1980) 400,000 tons SO2

Reactions with oxygen in air form SO3

2SO2 + O2 2 SO3

Reactions with water in air form acidsSO3 + H2O H2SO4 sulfuric acid

NO + H2O HNO2 nitrous acid

HNO2 + H2O HNO3 nitric acid

30

Effects of Acid Rain

Leaches Al from soil, which kills fish

Fish kills in spring from runoff due to

accumulation of large amounts of acid in

snow

Dissolves waxy coatings that protect leaves

from bacteria

Corrodes metals, textiles, paper and leather