Question

$X$ and $Y$ are two different elements having their atomic masses in 1:2 ratio. The compound formed by the combination of $X$ and $Y$ contains $50$% of $X$ by weight. The empirical formula of the compound is:

• A. $X_{2}Y$
• B. $X{Y}_2$
• C. $XY$
• D. $X_{4}Y$

Answer 1

Answer: (A)

$X_{2}Y$

Let the atomic mass of $X$ be $w$ and atomic mass of $Y$ is $2w$ (as they are in the ratio 1:2).

Given: compound $X$ = 50% by weight

So, compound $Y$ = (100-50)% = 50%

Since ratio of atomic masses of $X:Y$ is 1:2, we can write:

$X$ $=\frac{50}{1}=50$

$Y$ $=\frac{50}{2}=25$

Further, simplifying the ratios of 50:25 gives us 2:1

So, empirical formula is $X_{2}Y$