Practice pH Problems

Department of Nutrition Science

Purdue University



1. Convert the following pH values to [H+]: 6.37; 4.83.

2. Convert the following pOH values to [H+]: 3.28; 9.86.

3. Convert the following molar hydrogen ion concentrations to pH values: 0.0139; 2.07 x 10-5.

4. Calculate the pH of each of the following systems:

a. 40 ml of a solution containing 1.00 g of nitric acid.

b. 0.180 M benzoic acid solution

c. 0.120 M chloroacetic acid solution

d. a solution of 0.500 g of o-phthalic acid in 125 ml of water

5. Calculate the equilibrium concentration of H+, C2H5COO-, and C2H5COOH in a solution of 0.040 moles of propionic acid in 150 ml of water.

6. A 2% solution of a monoprotic acid, pKa = 5.2, had a pH of 3.5. What is the molecular weight of the acid?

7. A 0.01 M solution of phenol is 0.05% ionized at 25oC. What is the pKa of the acid?

8. What strength of formic acid (Ka = 1.76 x 10-4) solution should be prepared to give a pH of 3.8?

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