Q. If a pure compound is composed of $X_{2}Y_{3}$ molecules and consists of $60\%$ X by weight what is the atomic weight of $Y$ is term of atomic weight of $X$ (molecular mass of $X=M_{x}$ )?
NTA AbhyasNTA Abhyas 2020
Solution:
Element $\%$ weight $\%$ mole $X$ $60$ $60/M_{x}$ $Y$ $40$ $40/M_{y}$
given $\frac{60/M_{x}}{40/M_{y}}=\frac{2}{3}\Rightarrow \frac{M_{y}}{M_{x}}=\frac{4}{9}$
$M_{y}=\frac{4}{9}M_{x}$
| Element | $\%$ weight | $\%$ mole |
| $X$ | $60$ | $60/M_{x}$ |
| $Y$ | $40$ | $40/M_{y}$ |