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JAMB Chemistry 2020 Question 10

Question 10

Acids, Bases and Salts

Determine the PH of a 2.50×10−5M solution of potassium hydroxide.

  1. A.3.6
  2. B.9.4
  3. C.5.0
  4. D.12.0
Show the answer and explanation

Answer: B (9.4)

Explanation

KOH ionises fully, so [OH−] = 2.5 × 10−5 and pOH = −log(2.5 × 10−5) ≈ 4.6. pH = 14 − 4.6 = 9.4.