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 = ?

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

c = 0.25 mol/L
pH =
2.Easy
02468101214acidicneutralbasicpH 5.5

A solution has a pH of 5.5. Find the hydronium ion concentration [H₃O⁺] in mol/L.

pH = 5.5
[H₃O⁺] = mol/L
3.Medium
02468101214acidicneutralbasicpH = ?

Find the pH pH of a 0.5 mol/L solution of benzoic acid (Ka = 6.3 × 10⁻⁵).

c = 0.5 mol/LKa = 6.3 × 10⁻⁵
pH =
4.Medium
02468101214acidicneutralbasicpH = ?

Find the pH pH of a 0.05 mol/L solution of hypochlorous acid (Ka = 3 × 10⁻⁸).

c = 0.05 mol/LKa = 3 × 10⁻⁸
pH =
5.Hard
02468101214acidicneutralbasicpH = ?

A 1.00 L buffer contains 0.25 mol lactic acid and 0.15 mol of its conjugate base (Ka = 0.00014). 0.025 mol of NaOH is added. Find the new pH pH.

n(HA) = 0.25 moln(A⁻) = 0.15 moln(OH⁻) = 0.025 molKa = 0.00014
pH =
6.Hard
02468101214acidicneutralbasicpH = ?

A buffer contains 0.25 mol/L hypochlorous acid and 0.15 mol/L of its sodium salt. Ka = 3 × 10⁻⁸. Find the pH pH of the buffer.

[HA] = 0.25[A⁻] = 0.15Ka = 3 × 10⁻⁸
pH =

Answer key

  1. 1. pH = 0.6021
  2. 2. [H₃O⁺] = 3.162 × 10⁻⁶ mol/L
  3. 3. pH = 2.253
  4. 4. pH = 4.412
  5. 5. pH = 3.745
  6. 6. pH = 7.301

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