Molten sodium chloride conducts electricity due to the presence of

Which of the following solutions,upon electrolysis,produces $H_2$ gas at the cathode and $Cl_2$ gas at the anode?

Which of the following compounds gives ethane upon electrolysis of its aqueous solution?

When an aqueous solution of $CuCl_2$ is electrolysed using $Pt$ inert electrodes,the reactions at the cathode and anode respectively are:

If $0.50 \ L$ of a $0.60 \ M$ $SnSO_4$ solution is electrolyzed for a period of $30.0 \ min$ using a current of $4.60 \ A$ with inert electrodes,what is the final concentration of $Sn^{2+}$ remaining in the solution? (Atomic weight of $Sn = 119$)

For the extraction of sodium from $NaCl$,an electrolytic mixture of $NaCl + Na_3AlF_6 + CaCl_2$ is used. During the extraction process,only sodium is deposited at the cathode,while $K$ and $Ca$ are not,because: