pBlock ElementsII 1 Question 12
12. The product formed in the reaction of $\mathrm{SOCl}_{2}$ with white phosphorus is
(2014 Adv.)
(a) $\mathrm{PCl}_{3}$
(b) $\mathrm{SO}{2} \mathrm{Cl}{2}$
(c) $\mathrm{SCl}_{2}$
(d) $\mathrm{POCl}_{3}$
Show Answer
Solution:
- PLAN This problem is based on chemical properties of phosphorus.
White phosphorus on reaction with thionyl chloride $\left(\mathrm{SOCl}_{2}\right)$ produces phosphorus trichloride.
$\mathrm{P}{4}(s)+8 \mathrm{SOCl}{2}(l) \longrightarrow 4 \mathrm{PCl}{3}(l)+4 \mathrm{SO}{2}(g)+2 \mathrm{~S}{2} \mathrm{Cl}{2}(g)$
But if amount of thionyl chloride $\left(\mathrm{SOCl}_{2}\right)$ is in excess then it produces phosphorus pentachloride.
$\mathrm{P}{4}+10 \mathrm{SOCl}{2}(l) \longrightarrow 4 \mathrm{PCl}{5}+10 \mathrm{SO}{2}$
