Question

A binary compound of zinc and sulphur contains $67.1\%$ zinc by mass. The ratio of zinc and sulphur atoms in the compound is $x:y$. Then, $x+y$ is:

$[Zn=65;S=32]$

Answer 1

Let the mass of the compound is $100gm$

Mass of zinc $=67.1gm$

Mass of sulphur $=100-67.1=32.9gm$

Ratio of mass $Zn:S=67.1:32.9$

Ratio of moles $Zn:S=\frac{67.1}{65.3}:\frac{32.9}{32}$

Nearest integer ratio is $1:1$

So, the compound is $ZnS$

$x+y$ is $1+1=2$.