Which of the following reactions are correct with respect to the formation of products? I. $2…
Which of the following reactions are correct with respect to the formation of products?
I. $2 \mathrm{NaOH}+\mathrm{SO}_2 \longrightarrow \mathrm{Na}_2 \mathrm{SO}_4+\mathrm{H}_2$
II. $2 \mathrm{XeF}_4+3 \mathrm{O}_2 \mathrm{~F}_2 \stackrel{143 \mathrm{~K}}{\longrightarrow} 2 \mathrm{XeO}_3+7 \mathrm{~F}_2$
III. $\mathrm{PCl}_5+4 \mathrm{H}_2 \mathrm{O} \longrightarrow \mathrm{H}_3 \mathrm{PO}_4+5 \mathrm{HCl}$
IV. $2 \mathrm{NaNO}_2+2 \mathrm{HCl} \longrightarrow 2 \mathrm{NaCl}+\mathrm{NO}$
$+\mathrm{NO}_2+\mathrm{H}_2 \mathrm{O}$
II, IV
I, III
I, III
II, III
Solution
For the given reactions :
(I) $2 \mathrm{NaOH}+\mathrm{SO}_2 \longrightarrow \mathrm{Na}_2 \mathrm{SO}_4+\mathrm{H}_2$ is not correct. The correct reaction is
$
2 \mathrm{NaOH}+\mathrm{SO}_2 \longrightarrow \mathrm{Na}_2 \mathrm{SO}_3+\mathrm{H}_2 \mathrm{O}
$
(II) $2 \mathrm{XeF}_4+3 \mathrm{O}_2 \mathrm{~F}_2 \stackrel{143 \mathrm{~K}}{\longrightarrow} 2 \mathrm{XeO}_3+7 \mathrm{~F}_2$ is also not the correct reaction, the correct reaction is
$
\mathrm{XeF}_4+\mathrm{O}_2 \mathrm{~F}_2 \stackrel{143 \mathrm{~K}}{\longrightarrow} \mathrm{XeF}_6+\mathrm{O}_2
$
(III) $\mathrm{PCl}_5+4 \mathrm{H}_2 \mathrm{O} \longrightarrow \mathrm{H}_3 \mathrm{PO}_4+5 \mathrm{HCl}$ is the correct reaction, if occurs in two steps, as follows:
(i) $\mathrm{PCl}_5+\mathrm{H}_2 \mathrm{O} \longrightarrow \mathrm{POCl}_3+2 \mathrm{HCl}$
(ii) $\mathrm{POCl}_3+3 \mathrm{H}_2 \mathrm{O} \longrightarrow \mathrm{H}_3 \mathrm{PO}_4+3 \mathrm{HCl}$
Overall reaction,
$
\mathrm{PCl}_5+4 \mathrm{H}_2 \mathrm{O} \longrightarrow \mathrm{H}_3 \mathrm{PO}_4+5 \mathrm{HCl}
$
(IV) $2 \mathrm{NaNO}_2+2 \mathrm{HCl} \longrightarrow 2 \mathrm{NaCl}+\mathrm{NO}_2+\mathrm{H}_2 \mathrm{O}$ is also the correct reaction as $\mathrm{HCl}$ can decomposes salts like $\mathrm{NaNO}_2$ to $\mathrm{NaCl}, \mathrm{NO}_2$ and $\mathrm{H}_2 \mathrm{O}$.
Hence, option (b) is the correct answer