Question

Select the species acting as reductant and oxidant in the following.
$PCl_3 + Cl_2 \rightarrow PCl_5$

• A. $Cl_2$ is oxidant, $PCl_3$ is reductant.
• B. $Cl_2$ is reductant, $PCl_3$ is oxidant.
• C. Both are reductants.
• D. Both are oxidants.

Answer 1

Answer: (A)

$P^{3+} \rightarrow P^{5+} + 2e^{-}$
$Cl_2 + 2e^{-} \rightarrow 2Cl^{-}$
So, $P$ is being oxidised from $P^{3+}$ to $P^{5+}$. So, it is acting as reductant.
$Cl$ is being reduced from $Cl_2 (0)$ to $Cl^-(-1)$. So, it is acting as an oxidant.