Question

A compound contains two elements ${}^{\prime }{X}^{\prime }$ and ${}^{\prime }{Y}^{\prime }$ in the ratio of $50\%$ each. Atomic mass of ${}^{\prime }{X}^{\prime }$ is $20$ and ${}^{\prime }{Y}^{\prime }$ is $40$. What can be its simplest formula?

• A. $XY$
• B. $X_{2}Y$
• C. $X{Y}_2$
• D. $X_2{Y}_3$

Answer 1

Answer: (B)

Percentage of element ${}^{\prime }{X}^{\prime }=50$,
mole ratio $=\frac{50}{20}=2.5$
Percentage of element ${}^{\prime }{Y}^{\prime }=50$,
mole ratio $=\frac{50}{40}=1.25$
For ${}^{\prime }{X}^{\prime }$, simple ratio $=2.5/1.25=2$
For ${}^{\prime }{Y}^{\prime }$, simple ratio $=1.25/1.25=1$
Formula $=X_{2}Y$