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 H 3 O + ) 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. ___soap C. ___coffee D. ___ wine E. ___ water F. ___ grapefruit

6 Solution AB1 Describe each solution as: 1) acid 2) base or 3) neutral. A. _1_ soda B. _2_ soap C. _1_ coffee D. _1_ wine E. _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 HNO 3 nitric acid H 3 PO 4 phosphor ic acid H 2 SO 4 sulfur ic acid CH 3 COOH acet ic acid

10 Learning Check AB3 Give the names of the following A. HBr (aq)1. bromic acid 2. bromous acid 3. hydrobromic acid B. H 2 CO 3 1. carbonic acid 2. hydrocarbonic acid 3. carbonous acid

11 Solution AB3 A. HBr3. hydrobromic acid The 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. H 2 CO 3 1. carbonic acid The name of an oxyacid is named with the stem of the anion (carbonate) changed to -ic acid

12 Some Common Bases NaOHsodium 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. ___ HNO 2 1) hydrochloric acid B. ___Ca(OH) 2 2) sulfuric acid C. ___H 2 SO 4 3) sodium hydroxide D. ___HCl4) nitrous acid E. ___NaOH5) calcium hydroxide

14 Solution AB4 Match the formulas with the names: A. _4__ HNO 2 1) hydrochloric acid B. _5__Ca(OH) 2 2) sulfuric acid C. _2__H 2 SO 4 3) sodium hydroxide D. _1__HCl4) nitrous acid E. _3__NaOH5) calcium hydroxide

15 Learning Check AB5 Acid, Base Name or Salt CaCl 2 _______________________ KOH_______________________ Ba(OH) 2 ______ _________________ HBr_______________________ H 2 SO 4 ________________________

16 Solution AB5 Acid, Base Name or Salt CaCl 2 saltcalcium chloride KOHbasepotassiuim hydroxide Ba(OH) 2 basebarium hydroxide HBracidhydrobromic acid H 2 SO 4 acidsulfuric acid

17 Bronsted-Lowry Acids Acids are hydrogen ion (H +) donors Bases are hydrogen ion (H + ) acceptors HCl + H 2 O H 3 O + + Cl - donor acceptor + - +

18 pH Indicates the acidity [H 3 O + ] of the solution pH = - log [H 3 O + ] From the French pouvoir hydrogene (hydrogen power or power of hydrogen)

19 In the expression for [H 3 O + ] 1 x 10 -exponent the exponent = pH [H 3 O + ] = 1 x 10 -pH M pH

20 pH Range Neutral [H + ] > [OH - ] [H + ] = [OH - ] [OH - ] > [H + ] Acidic Basic

21 Some [H 3 O + ] and pH [H 3 O + ] pH 1 x M 5 1 x M 9 1 x M 11

22 pH of Some Common Acids gastric juice1.0 lemon juice2.3 vinegar2.8 orange juice3.5 coffee5.0 milk6.6

23 pH of Some Common Bases blood 7.4 tears 7.4 seawater 8.4 milk of magnesia10.6 household ammonia11.0

24 Learning Check pH4 A. The [H 3 O + ] of tomato juice is 1 x M. What is the pH of the solution? 1) - 42)43)8 B. The [OH - ] of an ammonia solution is 1 x M. What is the pH of the solution? 1) 32)113)-11

25 Solution pH4 A. pH = - log [ 1 x ] = -(- 4) = 4 B. [H 3 O + ] = 1 x pH = - log [ 1 x ] = -(- 11) = 11

26 Solution pH5 The pH of a soap is 10. What is the [H 3 O + ] of the soap solution? [H 3 O + ] = 1 x 10 -pH M = 1 x M

27 Acid Rain Unpolluted rain has a pH of 5.6 Rain with a pH below 5.6 is acid rain CO 2 in the air forms carbonic acid CO 2 + H 2 O H 2 CO 3 Adds to H + of rain H 2 CO 3 H + (aq) + HCO 3 -(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 N 2 SO 2 26 million tons in 1980 NO and NO 2 22 million tons in 1980 Mt. St Helens (1980) 400,000 tons SO 2 2. Reactions in the atmosphere form SO 3 2SO 2 + O 2 2 SO 3 3. Reactions with atmosphere water form acids SO 3 + H 2 O H 2 SO 4 sulfuric acid NO + H 2 O HNO 2 nitrous acid HNO 2 + H 2 O HNO 3 nitric acid 4. Effects of Acid Rain Decline in fish populations in rivers and lasts due to toxic effect of Al leached from soil by acid rain Extensive 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 bacteria Corrodes 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 N 2

29 SO 2 26 million tons in 1980 NO and NO 2 22 million tons in 1980 Mt. St Helens (1980) 400,000 tons SO 2 Reactions with oxygen in air form SO 3 2SO 2 + O 2 2 SO 3 Reactions with water in air form acids SO 3 + H 2 O H 2 SO 4 sulfuric acid NO + H 2 O HNO 2 nitrous acid HNO 2 + H 2 O HNO 3 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