In electrolysis of aqueous $NaOH$ at $NTP$,$2.8 \ L$ of oxygen gas is liberated at the anode. The amount of gas liberated at the cathode will be ............ $L$.

Which of the following elements is extracted commercially by the electrolysis of an aqueous solution of its compound?

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.

Which metal cannot be obtained by the electrolysis of its aqueous salt solution?

How many coulombs are provided by a current of $0.010 \ mA$ in the calculator battery that can operate for $1000 \ hours$?

When an aqueous solution of sodium sulfate $(Na_2SO_4)$ is electrolyzed,what are the products obtained at the cathode and anode,respectively?