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JAMB Chemistry 1989 Question 2

Question 2

Chemical Formulae and Equations

The molar ratio of carbon to hydrogen of a volatile liquid compound is 1:2. 0.12 g of the liquid on evaporation at s.t.p. gave 32 cm3 of vapour. The molecular formula of the liquid is [G.M.V = 22.4 dm3, C = 12, H = 1]

  1. A.C3H6
  2. B.C4H8
  3. C.C5C10
  4. D.C6H12
Show the answer and explanation

Answer: D (C6H12)

Explanation

Molar mass = 0.12 × 22400/32 = 84 g. The empirical formula CH2 has mass 14, and 84/14 = 6, so the formula is C6H12.