Which of the following materials from $Na, Hg, S, Pt,$ and graphite are used as electrodes in electrolytic cells containing aqueous solutions?

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.

In electroplating,which of the following metals is generally not used for plating?

$1 \ C$ of electricity deposits:

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 will give $H_{2(g)}$ at cathode and $O_{2(g)}$ at anode on electrolysis using platinum electrodes?