2Na + Cl\(_2\) → 2NaCl In the reaction above, the specie that undergoes reduction is

Reduction is the gain of electrons (or a decrease in oxidation state). To identify which species is reduced, track the oxidation states of each element.

In the reaction \(2\text{Na} + \text{Cl}_2 \rightarrow 2\text{NaCl}\):

• Sodium (Na): Oxidation state changes from 0 (in elemental Na) to +1 (in NaCl). This is an increase in oxidation state, meaning sodium is oxidised (it loses one electron per atom).
• Chlorine (Cl₂): Oxidation state changes from 0 (in elemental Cl₂) to -1 (in NaCl as Cl^-). This is a decrease in oxidation state, meaning chlorine is reduced (each Cl atom gains one electron).

The species that undergoes reduction is Cl₂, because it is the substance that accepts electrons and has its oxidation state lowered from 0 to -1.

Note that Cl^- is the product of the reduction, not the species that undergoes it. The question asks for the species that undergoes reduction, which is the reactant Cl₂.