How many moles of electrons (how many Faradays of electricity) are required to reduce $1 \ mol$ of $MnO_4^-$ to $MnO_2$?

On electrolysis of aqueous $CuSO_4$ solution using $Cu$ electrodes,if $2.5 \ g$ of $Cu$ is deposited at the cathode,then at the anode:

The mass of zinc produced by the electrolysis of zinc sulphate solution with a steady current of $0.015 \ A$ for $15$ minutes is . . . . . . $ \times 10^{-4} \ g$. (Atomic mass of zinc $= 65.4 \ amu$)

$108 \ g$ of silver (molar mass $108 \ g \ mol^{-1}$) is deposited at the cathode from $AgNO_3(aq)$ solution by a certain quantity of electricity. The volume (in $L$) of oxygen gas produced at $273 \ K$ and $1 \ bar$ pressure from water by the same quantity of electricity is ............. $L$.

How much current should be passed through acidified water for $100 \ s$ to liberate $0.224 \ L$ of $H_2$ gas at $STP$ (in $A$)?

$A$ current of $2 \ A$ passing for $5 \ hours$ through molten tin salt deposited $22.2 \ g$ of tin. The oxidation state of tin in the salt is . . . . . . . (Atomic mass of $Sn = 119$)