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Question
The empirical formula of a compound is C2H5. Its vapour density is 29. Determine the relative molecular mass of the compound and hence its molecular formula.
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Solution
Given the empirical formula of the compound is C2H5.
Vapour density is = 29 .
Empirical formula mass of the compound = 29
As, molecular mass = 2 x vapour density = 2 x 29 = 58
So, molecular mass of the compound =58
Molecular formula = n x Empirical formula
Now, n = Molecular mass/ Empirical formula mass = 58/ 29 =2
Molecular formula = 2 x (C2H5 ) = C4H10
So, molecular formula of compound is = C4H10
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