Acids & Bases

Definition Acid Base Arrhenius H+ producer OH- producer Bronsted-Lowry H+ donor H+ acceptor ** **this is the definition we will use for the rest of the unit

Arrhenius acid is a substance that produces H+ (H3O+) in water. Arrhenius base is a substance that produces OH- in water.

A Brønsted acid is a proton donor A Brønsted base is a proton acceptor conjugate acid conjugate base base acid

General Properties Acid base Sour taste Color changes in plant dyes React with metals to produce H2 gas React with carbonates and bicarbonates to produce CO2 gas Aqueous acid solutions conduct electricity Taste bitter Feel slippery Color changes in plant dyes Aqueous base solutions conduct electricity

Concentration Strength Based on how much is dissolved in solution Based on the ability of an acid or base to dissociate

Strength Strong Weak Strong Acid (HCl) Weak Acid (HF) Dissociate completely Partially dissociate Strong Acid (HCl) Weak Acid (HF)

Strong acids Strong bases NaOH KOH LiOH RbOH CsOH     Ca(OH)2 Ba(OH)2 Sr(OH)2 HI HBr HClO4 HCl H2SO4 HNO3

Strong Electrolyte – 100% dissociation NaCl (s) Na+ (aq) + Cl- (aq) H2O Weak Electrolyte – not completely dissociated CH3COOH CH3COO- (aq) + H+ (aq) Strong Acids are strong electrolytes HCl (aq) + H2O (l) H3O+ (aq) + Cl- (aq) HNO3 (aq) + H2O (l) H3O+ (aq) + NO3- (aq) Strong Bases are strong electrolytes NaOH (s) Na+ (aq) + OH- (aq) H2O Ba(OH)2 (s) Ba2+ (aq) + 2OH- (aq) H2O

Weak Bases are weak electrolytes F- (aq) + H2O (l) OH- (aq) + HF (aq) NO2- (aq) + H2O (l) OH- (aq) + HNO2 (aq) Weak Acids are weak electrolytes HF (aq) + H2O (l) H3O+ (aq) + F- (aq) HNO2 (aq) + H2O (l) H3O+ (aq) + NO2- (aq) HSO4- (aq) + H2O (l) H3O+ (aq) + SO42- (aq)

Calculating Concentration

Acid-Base Properties of Water H2O + H2O H3O+ + OH- acid conjugate base base conjugate acid autoionization of water H2O (l) H+ (aq) + OH- (aq)

The Ion Product of Water H2O (l) H+ (aq) + OH- (aq) Kw = [H+][OH-] The ion-product constant (Kw) is the product of the molar concentrations of H+ and OH- ions at a particular temperature. At 250C Kw = [H+][OH-] = 1.0 x 10-14

Acid-Base Solutions Solution Is [H+] = [OH-] neutral [H+] > [OH-] acidic [H+] < [OH-] basic

Example 1 The concentration of H+ ions in an aqueous solution is 1.0×1 0 −5 M. Calculate the concentration of OH − ions? Is the solution acidic, basic, or neutral?

Example 2 Calculate the concentration of OH − ions in a HCl solution whose hydrogen ion concentration is 1.3 M.

pH pH = -log [H+] [H+] = 10−pH [OH-] = 10−pOH pH + pOH = 14.00 pOH = -log [OH-] [H+] = [OH-] [H+] > [OH-] [H+] < [OH-] Solution Is neutral acidic basic [H+] = 1.0 x 10-7 [H+] > 1.0 x 10-7 [H+] < 1.0 x 10-7 pH = 7 pH < 7 pH > 7 At 250C [H+] pH

Example 1 What is the pH, pOH, and hydroxide ion concentration of a solution with a hydrogen ion concentration of 1.0×1 0 −6 M?

Example 2 What is the pH, pOH, and hydrogen ion concentration of a solution if the concentration of the hydroxide ions is 9.6×1 0 −4 M?