Question

Phosphorus reacts with $SO _{2} Cl _{2}$ to form $PCl _{5}$ and $X$. At $723\, K , HCl$ gas reacts with $O _{2}$ in the presence of $CuCl _{2}$ to form water and $Y . Y$ reacts with $X$ in water to form two acids $A$ and $B$. What are $A$ and $B$ respectively?

• A. $H _{2} SO _{4}, HCl$
• B. $H _{2} SO _{4}, HNO _{3}$
• C. $HCl , HNO _{3}$
• D. $H _{2} SO _{4}, H _{3} PO _{4}$

Answer 1

Answer: (A)

When thionyl chloride reacts with white phosphorus, phosphorus pentachloride and $SO _{2}$ is formed.

$P _{4}+10 SO _{2} Cl _{2} \ce{->}4 PCl _{5}+10 SO _{2}(X)$

At $723 K$, HCl gas reacts with $O _{2}$ in the presence of $CuCl _{2}$ to form water and $Cl _{2}(Y)$.

$4 HCl + O _{2} \ce{->[{723 K}][{CUCl_2}]}+2 H _{2} O \text { (Deacon process) }$

$Cl _{2}(Y)$ react with $SO _{2}(X)$ in water to form two acids $HCl (A)$ and $H _{2} SO _{4}(B)$.

$\underset{(X)}{ SO _{2}}+2 H _{2} O +\underset{(Y)}{ Cl _{2}} \ce{->} \underset{(B)}{2 HCl }+ H _{(A)} H _{2} SO _{4}$