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Acids and Bases

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In the expression for [H3O+] / [H+]

1 x 10-exponent

the exponent = pH

[H3O+] = 1 x 10-pH M

pH

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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

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Some [H3O+] and pH

[H3O+] pH

1 x 10-5 M 5

1 x 10-9 M 9

1 x 10-11 M 11

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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

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pH of Some Common Bases

blood 7.4

tears 7.4

seawater 8.4

milk of magnesia 10.6

household ammonia 11.0

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Examples

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

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pH Questions

Identify each solution as1. acidic 2. basic 3. neutral

A. ___ HCl with a pH = 1.5

B. ___ Pancreatic fluid [H+] = 1 x 10-8 M

C. ___ Sprite soft drink pH = 3.0

D. ___ pH = 7.0

E. ___ [OH-] = 3 x 10-10 M

F. ___ [H+] = 5 x 10-12

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Acids

• Produce H+ (as H3O+) ions in water

• Conduct Electricity (electrolytes)

• Taste sour

• Corrode metals

• React with bases to form salts and water• Formulas start with H• React with metals to form H2 gas.• Change the color of indicators

– (for example: blue litmus turns to red)

Acids Affect Indicators, by changing their color

Blue litmus paper turns red in contact with an acid (and red paper stays

red).

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Some Common Acids

HCl hydrochloric acid

HNO3 nitric acid

H3PO4 phosphoric acid

H2SO4 sulfuric acid

CH3COOH acetic acid

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Bases

Produce OH- ions in water

Formulas end in OH

Taste bitter, chalky

Are electrolytes

Feel soapy, slippery

React with acids to form salts and water

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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)

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Learning Check AB1Describe the solution in each of the following as: 1) acid 2) base or 3)neutral.A. ___soda

B. ___soapC. ___coffeeD. ___ wineE. ___ water

F. ___ grapefruit

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Solution AB1Describe 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

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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

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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

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Some Common Bases

NaOH sodium hydroxide

KOH potassium hydroxide

Ba(OH)2 barium hydroxide

Mg(OH)2 magnesium hydroxide

Al(OH)3 aluminum hydroxide

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Learning Check AB4

Identify each formula as an acid or base:

A. ___ HNO2

B. ___ Ca(OH)2

C. ___ H2SO4

D. ___ HClE. ___ NaOH

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Learning Check AB5

Acid, Base Nameor Salt

CaCl2 ______ _________________

KOH ______ _________________

Ba(OH)2 ______ _________________

HBr ______ _________________

H2SO4 ______ __________________

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Neutralization Reactions

* When acid and bases with equal amounts of hydrogen ion H+ and hydroxide ions OH- are mixed, the resulting solution is neutral. * Products are a salt and water* Salts formulas do not start with H or end in OH

NaOH (aq) + HCl(aq) NaCl + H2Obase acid salt water

Ca(OH)2 + 2 HCl CaCl2 + 2H2Obase acid salt water

Salt Hydrolysis• A salt is an ionic compound that:

–comes from the anion of an acid

–comes from the cation of a base

–is formed from a neutralization reaction

–some neutral; others acidic or basic

• “Salt hydrolysis” - a salt that reacts with water to produce an acid or base

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Learning Check AB5

Acid, Base Nameor Salt

CaCl2 ______ _________________

KOH ______ _________________

Ba(OH)2 ______ _________________

HBr ______ _________________

H2SO4 ______ __________________

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Solution AB5

Acid, Base Nameor Salt

CaCl2 salt calcium chloride

KOH base potassiuim hydroxide

Ba(OH)2 base barium hydroxide

HBr acid hydrobromic acid

H2SO4acid sulfuric acid