Molten sodium chloride conducts electricity due to the presence of

Which one of the following materials conducts electricity?

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:

On electrolysis of aqueous solution of $KI$ in the presence of platinum electrodes,which of the following statements are correct?
$(a)$ Hydrogen gas is released at the cathode.
$(b)$ Oxygen gas is released at the anode.
$(c)$ $pOH$ of the solution decreases.
$(d)$ There is deposition of potassium at the cathode.

Electrolysis of aqueous $HCl$ solution produces

Electrolysis of concentrated aqueous solution of $NaCl$ results in