Question

What is the reason Na acts as a reducing agent while chlorine acts as an oxidising agent in the reaction:
2Na _(s) + Cl_2(g)-------------- 2NaCl _(s)

Answer 1

The reaction can be broken down into following two half reactions:
$$\begin{gathered} Na\to N{a}^{+}+e^{-} \\ C{l}_2+2e^{-}\to 2C{l}^{-} \end{gathered}$$
Here, Na has lost an electron and thus it has increased its oxidation state from 0 to 1. Thus, it has been oxidised and acts as a reducing agent.
Cl, on the other hand has gained one electron due to which its oxidation state has decreased from 0 to -1. So, it has been reduced and thus acts as an oxidising agent.