pH & buffers worksheet with answers

Free printable pH & buffers worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
02468101214acidicneutralbasicpH 1.5

A solution has a pH of 1.5. Find the hydronium ion concentration [H₃O⁺] in mol/L.

pH = 1.5
[H₃O⁺] = mol/L
2.Easy
02468101214acidicneutralbasicpH = ?

Find the pH pH of a 0.25 mol/L solution of hydrochloric acid (HCl), a strong acid.

c = 0.25 mol/L
pH =
3.Medium
02468101214acidicneutralbasicpH = ?

Find the pH pH of a 0.25 mol/L solution of lactic acid (Ka = 0.00014).

c = 0.25 mol/LKa = 0.00014
pH =
4.Medium
02468101214acidicneutralbasicpH = ?

Find the pH pH of a 0.25 mol/L solution of hydrofluoric acid (Ka = 0.00068).

c = 0.25 mol/LKa = 0.00068
pH =
5.Hard
02468101214acidicneutralbasicpH = ?

A 1.00 L buffer contains 0.1 mol acetic acid and 0.1 mol of its conjugate base (Ka = 1.8 × 10⁻⁵). 0.01 mol of NaOH is added. Find the new pH pH.

n(HA) = 0.1 moln(A⁻) = 0.1 moln(OH⁻) = 0.01 molKa = 1.8 × 10⁻⁵
pH =
6.Hard
02468101214acidicneutralbasicpH = ?

A 1.00 L buffer contains 0.1 mol benzoic acid and 0.2 mol of its conjugate base (Ka = 6.3 × 10⁻⁵). 0.05 mol of NaOH is added. Find the new pH pH.

n(HA) = 0.1 moln(A⁻) = 0.2 moln(OH⁻) = 0.05 molKa = 6.3 × 10⁻⁵
pH =

Answer key

  1. 1. [H₃O⁺] = 0.03162 mol/L
  2. 2. pH = 0.6021
  3. 3. pH = 2.233
  4. 4. pH = 1.896
  5. 5. pH = 4.832
  6. 6. pH = 4.9

Full step-by-step solutions: practise this topic on examproblems.com.