Ka, Kb and percent ionization: Practice

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K

a

, K

b

and percent ionization: Practice

1.

Determine the K a

of a weak acid if a 0.300 M solution has a pH of 1.94.

2.

What is K b

for N

2

H

4

(hydrazine) if a 0.500 M solution has the following concentrations at equilibrium? [N

2

H

4

] = 0.499 M, [OH ] = 1.23 x 10 -3 M, [N

2

H

5

+ ] =

1.23 x 10 -3

3.

A solution of 1.00 M HA in water ionizes 2.00 %. Find K a

.

4.

A 0.250 M solution of a weak acid is 1.75 % ionized. Determine the pH and K a

of this solution.

5.

What is more acidic, a solution 0.100 M boric acid or a 0.100 M solution of nitrous acid? (see data booklet)

6.

C

5

H

5

N is a weak base. A 0.125M solution of this base has a pH of 9.10. Find the

K b

.

7.

Benzoic acid (C

6

H

5

COOH) is a weak acid. If K a

of benzoic acid is 6.46 x 10 -5 then find: a) the pH of a 0.0125 M solutionb) the % ionization of this solution

8.

What is the percent ionization in 0.0200 M HClO? K a

= 3.16 x 10 -8

9.

What is the ethanoate ion concentration in a 0.0178 M solution of ethanoic acid?

10.

What would be the hydrogen ion concentration in a 0.884 M solution of hydrocyanic acid?

11.

The ionization constant of a weak acid is 5.50 x 10 -5 . Find the percent ionization of a 0.0150M solution of the acid.

12.

Ammonia, NH

3

, is a weak base. Find the pH of a 0.150M solution of this base.

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