Question

A compound consisting of two elements, $X$ and $Y$ has equal mass of them. If their atomic weights are $30$ and $20$ respectively, the molecular formula of that compound (Mol. wt. $=120$) could be :

• A. $X_2{Y}_2$
• B. $X_3{Y}_3$
• C. $X_2{Y}_3$
• D. $X_3{Y}_2$

Answer 1

The correct option is C $X_2{Y}_3$

The molar ratio is given by,
$X$ : $Y$
$\frac{w}{30}:\frac{w}{20}$ $=20:30=2:3$
The formula is $X_2{Y}_3$.