Give reason why:
$(i)$ Sodium acts as a reducing agent while chlorine acts as an oxidising agent in the following reaction:
$2 Na (s) + Cl_2 (g) \rightarrow 2 NaCl (s)$

(N/A) In the reaction $2 Na (s) + Cl_2 (g) \rightarrow 2 NaCl (s)$:
$1$. Sodium $(Na)$ loses electrons to form sodium ions $(Na^+)$. The process of loss of electrons is called oxidation. Since sodium undergoes oxidation and facilitates the reduction of chlorine,it acts as a reducing agent.
$2$. Chlorine $(Cl_2)$ gains electrons to form chloride ions $(Cl^-)$. The process of gain of electrons is called reduction. Since chlorine undergoes reduction and facilitates the oxidation of sodium,it acts as an oxidising agent.