Question

Elements P and Q react to form a compound $P_x{Q}_y$. R and P react to form $R_y{P}_z$.

If $P_x{Q}_y$ is a binary acid with x = 2y then the acid is:

• A. sulphuric acid
• B. hydrochloric acid
• C. chloric acid
• D. hydrogen sulphide

Answer 1

The correct option is D hydrogen sulphide

The molecular formula of the acids are as follows:

sulphuric acid: $H_{2}S{O}_4$

hydrochloric acid: $HCl$

Chloric acid:$HCl{O}_3$

Hydrogen sulphide: $H_{2}S$

Since the given acid is binary, P must be hydrogen. Also, $x=2y$ is satisfied only by $H_{2}S$. Hence the compound is $H_{2}S$