Given that $E^o_{Fe^{2+}/Fe} = -0.44 \ V$,$E^o_{Cu^{2+}/Cu} = 0.34 \ V$,and $E^o_{Ag^+/Ag} = 0.80 \ V$. Which of the following statements is correct?

What are the uses of standard half-cell potential?

Match List-$I$ with List-$II$.

List-$I$ (Conversion)	List-$II$ (Number of Faraday required)
$A$. $1 \ mol$ of $H_2O$ to $O_2$	$I$. $3 \ F$
$B$. $1 \ mol$ of $MnO_4^{-}$ to $Mn^{2+}$	$II$. $2 \ F$
$C$. $1.5 \ mol$ of $Ca$ from molten $CaCl_2$	$III$. $1 \ F$
$D$. $1 \ mol$ of $FeO$ to $Fe_2O_3$	$IV$. $5 \ F$

Choose the correct answer from the options given below:

Impure copper containing $Fe$,$Au$,and $Ag$ as impurities is electrolytically refined. $A$ current of $140 \ A$ for $482.5 \ s$ decreased the mass of the anode by $22.26 \ g$ and increased the mass of the cathode by $22.011 \ g$. The percentage of iron in the impure copper is (Given molar mass $Fe = 55.5 \ g \ mol^{-1}$,molar mass $Cu = 63.54 \ g \ mol^{-1}$)

At $T(K)$,the molar conductivity of $0.04 \ M$ acetic acid is $7.8 \ S \ cm^2 \ mol^{-1}$. If the limiting molar conductivities of $H^{+}$ and $CH_3COO^{-}$ at $T(K)$ are $349$ and $41 \ S \ cm^2 \ mol^{-1}$ respectively,the dissociation constant of acetic acid is

The reduction potentials of four elements $P, Q, R,$ and $S$ are $-2.90 \ V, +0.34 \ V, +1.20 \ V,$ and $-0.76 \ V$ respectively. The order of decreasing reactivity is: