For the feasibility of a redox reaction in a cell,the e.m.f. should be

If in a galvanic cell,the hydrogen half-cell is the cathode on the right side,what is the sign of the standard electrode potential of such a galvanic cell? Give an example.

Given:
$Co^{3+} + e^- \longrightarrow Co^{2+}; E^o = 1.81 \ V$
$Pb^{4+} + 2e^- \longrightarrow Pb^{2+}; E^o = + 1.67 \ V$
$Ce^{4+} + e^- \longrightarrow Ce^{3+}; E^o = + 1.61 \ V$
$Bi^{3+} + 3e^- \longrightarrow Bi; E^o = + 0.20 \ V$
Oxidizing power of the species will increase in the order:

The standard electrode potentials of $Ag^{+}/Ag$,$Hg_2^{2+}/2Hg$,$Cu^{2+}/Cu$,and $Mg^{2+}/Mg$ are $0.80 \ V$,$0.79 \ V$,$0.34 \ V$,and $-2.37 \ V$,respectively. An aqueous solution containing $1 \ M$ concentration of each of these metal salts is electrolyzed. With increasing voltage,what is the correct sequence of deposition of the metals at the cathode?

If standard reduction potentials $(E^0)$ of $(Al^{+3}_{(aq)}|Al(s))$, $(Fe^{+2}_{(aq)}|Fe(s))$, $(Cu^{+2}_{(aq)}|Cu(s))$ and $(Ag^{+1}_{(aq)}|Ag(s))$ are $-1.66 \text{ V}$, $-0.44 \text{ V}$, $+0.34 \text{ V}$ and $+0.79 \text{ V}$ respectively, which of the following reactions is non-spontaneous?

At ${25 \, ^\circ C}$,the standard reduction potentials for $Li^+/Li$,$Ba^{2+}/Ba$,$Na^+/Na$,and $Mg^{2+}/Mg$ are $-3.05 \, V$,$-2.73 \, V$,$-2.71 \, V$,and $-2.36 \, V$ respectively. Which of the following is the strongest oxidizing agent?