If we use molten NaCl, the products of electrolysis are ____________.

The correct option is:
$\begin{array}{c}\text{Sodium metal and}{\mathrm{Cl}}_2\text{gas}\end{array}$

Step-by-step Explanation:

1. Understanding Molten NaCl:
When sodium chloride (NaCl) is in its molten (liquid) state, it dissociates completely into its constituent free-moving ions because there is no water (solvent) present. The only ions present in the melt are:
• Cations: Sodium ions (${\mathrm{Na}}^{+}$)
• Anions: Chloride ions (${\mathrm{Cl}}^{-}$)

2. Behavior at the Electrodes during Electrolysis:
When an electric current is passed through molten NaCl using inert electrodes, the ions migrate towards the oppositely charged electrodes:

At the Cathode (Negative Electrode):
The positively charged sodium ions (${\mathrm{Na}}^{+}$) migrate towards the cathode, where they undergo reduction by gaining electrons to form metallic sodium:
${\mathrm{Na}}^{+}\left(l\right)+e^{-}\to \mathrm{Na}\left(l\right)$
Thus, sodium metal is deposited at the cathode.

At the Anode (Positive Electrode):
The negatively charged chloride ions (${\mathrm{Cl}}^{-}$) migrate towards the anode, where they undergo oxidation by losing electrons to form chlorine gas:
$2{\mathrm{Cl}}^{-}\left(l\right)\to {\mathrm{Cl}}_2\left(g\right)+2e^{-}$
Thus, chlorine gas (${\mathrm{Cl}}_2$ gas) is liberated at the anode.

Conclusion:
Since there is no water to compete at the electrodes (unlike in aqueous NaCl solution, where hydrogen gas is produced at the cathode), the only products of the electrolysis of molten NaCl are sodium metal and chlorine gas.