Question

In the reaction ${\mathrm{PCl}}_3+{\mathrm{Cl}}_2\to {\mathrm{PCl}}_5$

• A. ${PCl}_3$ is acting as reductant.
• B. ${Cl}_2$ is acting as reductant.
• C. Both ${PCl}_3$ and ${Cl}_2$are acting as reductant.
• D. Both ${PCl}_3$ and ${Cl}_2$are acting as oxidant.

Answer 1

The correct option is A

${\mathrm{PCl}}_3$ is acting as reductant.

Explanation:

• The substances which have the ability to oxidize others and get reduced by themselves are known as oxidizing agents or oxidants. Whereas the substances which have the ability to reduce others and get oxidized by themselves are known as reducing agents or reductants.
• The given reaction is as follows:
• ${\mathrm{PCl}}_3\left(\mathrm{g}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to {\mathrm{PCl}}_5\left(\mathrm{g}\right)$
• The oxidation state of Phosphorus ($\mathrm{P}$) changes from +3 in Phosphorus trichloride (${\mathrm{PCl}}_3$) to +5 in Phosphorus pentachloride (${\mathrm{PCl}}_5$). Thus, ${\mathrm{PCl}}_3$ is getting oxidized and therefore it acts as a reducing agent or reductant.
• The oxidation state of Chlorine ($\mathrm{Cl}$) changes from 0 in Chlorine gas (${\mathrm{Cl}}_2$) to -1 in Phosphorus pentachloride (${\mathrm{PCl}}_5$). Thus, ${\mathrm{Cl}}_2$ is getting reduced and therefore it acts as an oxidizing agent or oxidant.

Final Answer:

Hence, the correct option is (A) ${\mathrm{PCl}}_3$ is acting as a reductant.