What is $emf$?

What is the decreasing order of deposition of metal on electrode if standard reduction potentials are given as: $Ag^{+} | Ag = 0.80 \ V$,$Cu^{2+} | Cu = 0.337 \ V$,$Sn^{2+} | Sn = -0.136 \ V$,$Cd^{2+} | Cd = -0.403 \ V$?

If the $E^{0}$ values for $Mg^{+2} | Mg$,$Zn^{+2} | Zn$,and $Fe^{+2} | Fe$ are $-2.37 \ V$,$-0.76 \ V$,and $-0.44 \ V$ respectively,which statement is correct?

The standard electrode potential $({E^o})$ for $OCl^{-} / Cl^{-}$ and $Cl^{-} / \frac{1}{2}Cl_2$ respectively are $0.94 \ V$ and $-1.36 \ V$. The ${E^o}$ value for $OCl^{-} / \frac{1}{2}Cl_2$ will be ............... $V$.

Which of the following reactions exhibits the minimum standard reduction potential?

Standard reduction electrode potentials of three metals $A$,$B$,and $C$ are respectively $+0.5 \ V$,$-3.0 \ V$,and $-1.2 \ V$. The reducing powers of these metals are