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JAMB Chemistry 1984 Question 50

Question 50

Mole Concept and Stoichiometry

At S.T.P. how many litres of hydrogen can be obtained from the reaction of 500 cm3 of 0.5 M H2SO4 with excess zinc metal? (Gram molecular volume of H2 = 22.4 dm3).

  1. A.22.4 dm3
  2. B.11.2 dm3
  3. C.6.5 dm3
  4. D.5.6 dm3
  5. E.0.00 dm3
Show the answer and explanation

Answer: D (5.6 dm3)

Explanation

Moles of acid = 0.5 × 0.5 = 0.25 mol, and Zn + H2SO4 → ZnSO4 + H2 gives 0.25 mol of H2. Volume = 0.25 × 22.4 = 5.6 dm3.