Which of the following compounds is not obtained when the products obtained from the electrolysis of brine are mixed?

During the electrolysis of cryolite,aluminium and fluorine are formed in $........$ molar ratio :

Predict the products of electrolysis in each of the following:
$i$. An aqueous solution of $AgNO_3$ with silver electrodes
$ii$. An aqueous solution of $AgNO_3$ with platinum electrodes
$iii$. $A$ dilute solution of $H_2SO_4$ with platinum electrodes
$iv$. An aqueous solution of $CuCl_2$ with platinum electrodes.

Which is the simplest electrolytic cell? Give a detailed note on it.

On electrolysing a solution of dilute $H_2SO_4$ between platinum electrodes,the gas evolved at the anode is

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?