Question

A compound made up of two elements X and Y has an empirical formula X₂Y. If the atomic weight of X is 10 and that of Y is 5 and the compound ha a vapor density 25, find its molecular formula.

Answer 1

Empirical formula = X₂Y

Atomic Weight (X) = 10

Atomic Weight (Y) = 5

Empirical Formula Weght = 2 × 10 + 5 = 25

So, n = `"Molecular weight"/"Empirical formula weight" = (2xx"V.D")/"Empirical formula weight"`

`n = (2 xx 25)/25 = 2`

So Molecular Formula =  (X₂Y) × 2 = X₄Y₂