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.

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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 0.005 mol/L solution of hydrochloric acid (HCl), a strong acid.

c = 0.005 mol/L
pH =
3.Medium
02468101214acidicneutralbasicpH = ?

Find the pH pH of a 0.1 mol/L solution of benzoic acid (Ka = 6.3 × 10⁻⁵).

c = 0.1 mol/LKa = 6.3 × 10⁻⁵
pH =
4.Medium
02468101214acidicneutralbasicpH = ?

Find the pH pH of a 0.2 mol/L solution of hydrofluoric acid (Ka = 0.00068).

c = 0.2 mol/LKa = 0.00068
pH =
5.Hard
02468101214acidicneutralbasicpH = ?

A buffer contains 0.2 mol/L formic acid and 0.15 mol/L of its sodium salt. Ka = 0.00018. Find the pH pH of the buffer.

[HA] = 0.2[A⁻] = 0.15Ka = 0.00018
pH =
6.Hard
02468101214acidicneutralbasicpH = ?

A buffer contains 0.25 mol/L hydrofluoric acid and 0.8 mol/L of its sodium salt. Ka = 0.00068. Find the pH pH of the buffer.

[HA] = 0.25[A⁻] = 0.8Ka = 0.00068
pH =

Answer key

  1. 1. [H₃O⁺] = 0.03162 mol/L
  2. 2. pH = 2.301
  3. 3. pH = 2.606
  4. 4. pH = 1.946
  5. 5. pH = 3.62
  6. 6. pH = 3.673

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