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Acids Lesson 5 Acid Rain & Hydrolysis. Acid Rain. Acid Rain is caused by acid anhydrides. N O 2. N 2 O 4. automobile pollution. S O 2. S O 3. coal & smelter pollution. SO 3. + H 2 O. → H 2 SO 4(aq). Rain. Acid Rain has pH < 5.
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Acids Lesson 5 Acid Rain & Hydrolysis
Acid Rain Acid Rainis caused by acidanhydrides NO2 N2O4 automobile pollution SO2 SO3 coal & smelter pollution SO3 + H2O → H2SO4(aq) Rain Acid Rainhas pH < 5
Normal Rainhas pH = 6 due to dissolved CO2 CO2 + H2O → H2CO3 Acid raindissolves metal, limestone, concrete structures. Acid raindecreases the pH of lakes and causes toxic metals to leach into them.
Hydrolysis of Salts 1. Neutral Salts Consider the acid and base that makes NaCl NaCl HCl + NaOH → NaCl + HOH strong acid strong base neutral 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 ions from strong parents that are neutral.
Cross off all bold ions- they do not hydrolyze and are neutral Neutral Acidic
Cross off all bold ions- theydo not hydrolyze and are neutral Neutral Remaining amphriprotic ions are acidic Acidic Basic
A neutral salt will dissociate in water NaCl → Na+ + Cl- no ions to hydrolyze- neutral Cross off ions from strong parents that are neutral.
Hydrolysis of Salts 2. Basic Salts Consider NaCN Consider the acid and base that makes NaCN HCN + NaOH → NaCN + HOH weak acid strong base basic salt
A basic salt will first dissociatein water NaCN → Na+ + CN- neutral base- negative ions are bases + H2O CN- ⇄ HCN + OH- Hydrolysis
Hydrolysis of Salts 3. Acidic Salts NH4Cl HCl + NH3 → NH4Cl strong acid weak base acid salt
NH4Cl → NH4+ + Cl- positive ion- acid acid neutral + NH3 + H2O NH4+ ⇄ H3O+ Hydrolysis
4. Acidic Salts FeCl3 3HCl + Fe(OH)3 → FeCl3 + 3HOH strong acid weak base acid salt
H2O H2O H2O Fe3+ OH- H2O H2O H2O
H2O Hydronium ion H2O H2O Fe3+ H+ OH- H2O H H O H2O
positive ion - acid FeCl3 → Fe3+ + 3Cl- Look for the reaction on the acid chart! Fe(H2O)63+⇄ H+ + Fe(H2O)5(OH)2+ Hydrolysis- when the positive or negative ion in a salt reacts with water as an acid or base.