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JAMB Chemistry 1979 Question 15

Question 15

Mole Concept and Stoichiometry

How many grams of HBr would exactly be required to react with 2 g of propyne? (C = 12, H = 1, Br = 80)

  1. A.4.1 g
  2. B.6.1 g
  3. C.8.1 g
  4. D.10.1g
  5. E.16.2g
Show the answer and explanation

Answer: C (8.1 g)

Explanation

Propyne C3H4 (40 g/mol) adds 2 HBr across its triple bond. 2 g = 0.05 mol, which needs 0.10 mol HBr = 0.10 × 81 = 8.1 g.