The products formed when an aqueous solution of $NaBr$ is electrolysed in a cell having inert electrodes are

Given below are two statements $:$
$1 \ M$ aqueous solution of each of $Cu(NO_3)_2, AgNO_3, Hg_2(NO_3)_2$ and $Mg(NO_3)_2$ are electrolysed using inert electrodes.
Given $: E_{Ag^{+}/Ag}^{\theta} = 0.80 \ V, E_{Hg_2^{2+}/Hg}^{\theta} = 0.79 \ V, E_{Cu^{2+}/Cu}^{\theta} = 0.24 \ V$ and $E_{Mg^{2+}/Mg}^{\theta} = -2.37 \ V$.
Statement $(I) :$ With increasing voltage,the sequence of deposition of metals on the cathode will be $Ag, Hg$ and $Cu$.
Statement $(II) :$ Magnesium will not be deposited at cathode instead oxygen gas will be evolved at the cathode.
In the light of the above statement,choose the most appropriate answer from the options given below.

What is a rectifier?

Electrolysis of $KCl \cdot MgCl_2 \cdot 6H_2O$ gives

Which of the following is not a conductor of electricity?

During the electrolysis of $NaCl$ solution,$H_2$ gas is liberated at the cathode when a $Pt$ electrode is used,whereas sodium amalgam is formed when a $Hg$ cathode is used. What is the reason for this?