Dissociation and PH

The acid-dissociation constant for chlorous acid, HClO2, at 25 degrees C is 0.01. Calculate the concentration of H^+ if the initial concentration of acid is 0.100 M..

• 1.0 X 10^-3

• 1.0 X 10^-2

• 2.7 X 10^-2

• 3.7 X 10^-2

• 3.2 X 10^-2

Determine the pH of a 0.15-M aqueous solution of KF. For hydrofluoric acid, Ka = 1.47 X 10^-4.

• 5.83

• 6.59

• 8.16

• 2.33

• 12.01

The Ka for formic acid (HCHO2) is 1.8 X 10^-4. What is the pH of a 0.35-M aqueous solution of sodium formate (NaCHO2)?

• 2.68

• 4.32

• 5.35

• 2.10

• 1.65

The value of the acid-dissociation constant, Ka, for a weak monoprotic acid HA is 2.5 × 10^−6 . The pH of 0.40 M HA is closest to:

• 2.0

• 3.0

• 4.0

• 6.0

• 8.0

The pH of a 0.40 solution HOBr is 5.05. Calculate K_a of this solution.

• 1.98 X 10^-10

• 2.23 X 10^-5

• 5.05 X 10^-8

• 1.15 X 10^-11

An acidic solution has a pH of 3.4 pH with an acid dissociation constant K_a of 4.0 X 10^-7. What is the molarity of this weak acid.

• 0.10 M

• 0.20 M

• 0.40 M

• 995 M

What is the K_a of a solution with a pH of 6.8 and a Molarity of 4.5?

• 3.52 X 10^-8

• 5.58 X 10^-15

• 1.40 X 10^-1

• 1.51 X 10^-3