In the industrial production of which of the following,molecular hydrogen is obtained as a byproduct?

During the electrolysis of aqueous $NaCl$,if $3 \ mole$ of $H_2O$ are electrolysed,then how much charge (in $F$) is required if the current efficiency is $75 \ \%$?

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.

In the electrolysis of molten $NaCl$,what happens at the anode?

The number of electrons passing per second through a cross-section of copper wire carrying $10^{-6} \ A$ of current is found to be:

Which gas is produced at the cathode when $NaOH$ is prepared by the chlor-alkali process?