Acids Lesson 6 Acid Rain & Hydrolysis

Acid Rain The cause of Acid Rain is the release of acid anhydrides into the environment. Acid Anhydrides are nonmetal oxides. NO 2 N 2 O 4 automobile pollution SO 2 SO 3 coal & smelter pollution SO 3 +H 2 O→H 2 SO 4(aq) Rain Acid Rain has pH < 5

Normal Rain has pH = 6 due to dissolved CO 2 CO 2 +H 2 O→H 2 CO 3 Acid rain dissolves metal, limestone, concrete structures. Acid rain decreases the pH of lakes and causes toxic metals to leach into them.

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 1.Neutral Salts ConsiderNaCl The neutralization equation used to produce NaCl will tell us what kind of salt it is.

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 1.Neutral Salts ConsiderNaCl The neutralization equation used to produce NaCl will tell us what kind of salt it is. →NaCl +HOH

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 1.Neutral Salts ConsiderNaCl The neutralization equation used to produce NaCl will tell us what kind of salt it is. H + OH→NaCl +HOH

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 1.Neutral Salts ConsiderNaCl The neutralization equation used to produce NaCl will tell us what kind of salt it is. HCl+NaOH→NaCl +HOH

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 1.Neutral Salts ConsiderNaCl The neutralization equation used to produce NaCl will tell us what kind of salt it is. HCl+NaOH→NaCl +HOH strong acidstrong baseneutral salt

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 1.Neutral Salts ConsiderNaCl The neutralization equation used to produce NaCl will tell us what kind of salt it is. HCl+NaOH→NaCl +HOH strong acidstrong baseneutral salt When the acid and base parents are both strong the salt is always neutral. -

A neutral salt will dissociate in water. NaCl → Na + +Cl - Cross off the both ions that come from strong parents as they do not hydrolyze or react further with water- they are neutral. no ions to hydrolyze- neutral

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 2.Basic Salts ConsiderNaCN

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 2.Basic Salts ConsiderNaCN H + OH→NaCN +HOH

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 2.Basic Salts ConsiderNaCN HCN+NaOH→NaCN +HOH

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 2.Basic Salts ConsiderNaCN HCN+NaOH→NaCN +HOH weak acidstrong basebasic salt

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 2.Basic Salts ConsiderNaCN HCN+NaOH→NaCN +HOH weak acidstrong basebasic salt

A basic salt will first dissociate in water NaCN → Na + +CN - Cross off the Na + because it has a strong parent and does not hydrolyze- it is neutral Then the CN - ion, from the weak parent, will hydrolyze (react with water) as a Bronsted base. CN - +H 2 O ⇄ HCN+OH - negative ion left- basic

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 3.Acidic Salts ConsiderNH 4 Cl →NH 4 Cl

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 3.Acidic Salts ConsiderNH 4 Cl HCl+NH 3 →NH 4 Cl

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 3.Acidic Salts ConsiderNH 4 Cl HCl+NH 3 →NH 4 Cl strong acidweak baseacid salt

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 3.Acidic Salts ConsiderNH 4 Cl HCl+NH 3 →NH 4 Cl strong acidweak baseacid salt

An acidic salt will first dissociate in water NH 4 Cl → NH 4 + +Cl - Cross off the Cl - because it has a strong parent and does not hydrolyze- it is neutral Then the NH 4 + ion, from the weak parent, will hydrolyze (react with water) as a Bronsted acid. NH 4 + +H 2 O ⇄ H 3 O + +NH 3 positive ion left- acidic

Hydrolysis of Salts Salts can be acidic, basic, or neutral. 4.Acidic Salts ConsiderFeCl 3 3HCl+Fe(OH) 3 →FeCl 3 +3HOH strong acidweak baseacid salt

FeCl 3 → Fe 3+ +3Cl - The Fe 3+ ion is an acid Fe(H 2 O) 6 3+ ⇄ H + +Fe(H 2 O) 5 (OH) 2+ You can copy these complex reactions right off the acid chart! positive ion left- acidic