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Question
A compound of X and Y has the empirical formula XY2. Its vapor density is equal to its empirical formula weight. Determine its molecular formula.
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Solution
Given:
Empirical formula = XY2
Vapor density = Empirical formula weight
Molecular formula =?
Molecular weight = n(Empirical formula weight)
= 2 x V.D.
n(Empirical formula weight) = 2 x V.D.
Since Vapour density Empirical formula weight
n = 2
Molecular formula = 2(Empirical formula)
= 2(XY2)
Molecular formula = X2Y4
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