1. pH =3.56 [H ⁺]= ________.

2. The equilibrium constant for the reaction: HCN(aq) = H ⁺ (aq) + CN^- (aq) is 1x10^-10 . Initially the system contains only HCN in the concentration of 2 M. At equilibrium:

a) If the [H ⁺] is x, what are the [CN ^-] and the [HCN] equal to?

b) What is the approximate concentration of HCN?

c) Calculate the concentration of H ⁺ at equilibrium

3. What is the % ionization of chloroacetic acid in a 0.25 M solution?

Ka (Chloroacetic) = 1.4x10 ^-3

 (answer = 7.6%)

4. Lactic acid has one acid H. A 0.1 M solution has a pH of 2.44; what is the Ka?

 (answer = 1.3x10^-4 )

5. Calculate the value of the equilibrium constants for the following reactions from the value of Ka=1.8x10^-5 for AcOH and Kw.

a) AcO ^- (aq) + H ⁺ (aq) = HOAc(aq)

b) HOAc(aq) + OH^- (aq) = H₂O(l) + AcO^- (aq)

c) AcO^- (aq) + H₂O(l) = AcOH(aq) + OH^-

Ka of acetic acid is 1.8x10^-5

 6. What is the pH of a 0.56 M solution of NH₃?

 (answer = 11.5)