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 = ?

Find the pH pH of a 0.001 mol/L solution of Ba(OH)2, a strong base, at 25 °C.

c = 0.001 mol/L
pH =
2.Easy
02468101214acidicneutralbasicpH = ?

Find the pH pH of a 0.02 mol/L solution of hydrochloric acid (HCl), a strong acid.

c = 0.02 mol/L
pH =
3.Medium
02468101214acidicneutralbasicpH = ?

Find the pH pH of a 0.5 mol/L solution of lactic acid (Ka = 0.00014).

c = 0.5 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 0.25 mol lactic acid and 0.2 mol of its conjugate base (Ka = 0.00014). 0.01 mol of NaOH is added. Find the new pH pH.

n(HA) = 0.25 moln(A⁻) = 0.2 moln(OH⁻) = 0.01 molKa = 0.00014
pH =
6.Hard
02468101214acidicneutralbasicpH = ?

A 1.00 L buffer contains 0.3 mol hypochlorous acid and 0.15 mol of its conjugate base (Ka = 3 × 10⁻⁸). 0.05 mol of NaOH is added. Find the new pH pH.

n(HA) = 0.3 moln(A⁻) = 0.15 moln(OH⁻) = 0.05 molKa = 3 × 10⁻⁸
pH =

Answer key

  1. 1. pH = 11.3
  2. 2. pH = 1.699
  3. 3. pH = 2.081
  4. 4. pH = 1.896
  5. 5. pH = 3.796
  6. 6. pH = 7.426

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