What happens to the $pH$ during the electrolysis of aqueous $CuSO_4$ using platinum electrodes?

An aqueous solution containing $1 \ M$ each of $Cu(NO_3)_2$,$AgNO_3$,$Hg_2(NO_3)_2$,and $Mg(NO_3)_2$ is electrolyzed using inert electrodes. Given the standard reduction potentials: $E^{\circ}_{Ag^+/Ag} = 0.80 \ V$,$E^{\circ}_{Hg_2^{2+}/2Hg} = 0.79 \ V$,$E^{\circ}_{Cu^{2+}/Cu} = 0.34 \ V$,and $E^{\circ}_{Mg^{2+}/Mg} = -2.37 \ V$. What is the correct order of deposition of metals at the cathode?

Which gas is produced during the preparation of $NaOH$?

Which of the following is $NOT$ produced during the electrolysis of brine solution?

Explain: Oxidation of $Cl^{-}$ ion is carried out near the anode when electrolysis of aqueous (concentrated) $NaCl$ solution is carried out using an inert electrode.

The main reason for not using a mercury electrolytic cell in $NaOH$ manufacture is that