Which metal cannot produce $H_2$ gas by reaction with $HCl$ solution?
$E^0_{Fe^{2+}/Fe} = -0.44 \ V$
$E^0_{Cu^{2+}/Cu} = +0.34 \ V$
$E^0_{Ni^{2+}/Ni} = -0.25 \ V$
$E^0_{Zn^{2+}/Zn} = -0.76 \ V$

Given $E_{Cu^{2+}/Cu}^{\circ} = 0.34 \ V$ and $E_{Cu^{2+}/Cu^{+}}^{\circ} = 0.15 \ V$. Calculate the standard electrode potential $E_{Cu^{+}/Cu}^{\circ}$ in $V$.

Fill in the blanks :
$1$. ...... metal is the strongest reducing agent in aqueous solution.
$2$. ...... gas is the strongest oxidizing agent.
$3$. The standard reduction potential of any electrode is measured with reference to ......

If standard reduction potential $(E^{\circ})$ of $(Ni_{(aq)}^{+2} \mid Ni_{(s)})$ and $(Al_{(aq)}^{+3} \mid Al_{(s)})$ are $-0.25 \ V$ and $-1.66 \ V$ respectively,what is the standard emf of the cell reaction $2 \ Al_{(s)} + 3 \ Ni_{(aq)}^{+2} \rightarrow 2 \ Al_{(aq)}^{+3} + 3 \ Ni_{(s)}$?

The standard reduction electrode potentials of four metals are $A = -0.250 \ V$,$B = -0.140 \ V$,$C = -0.126 \ V$,and $D = -0.402 \ V$. Which metal can displace $A$ from its aqueous salt solution?

Given:
$E^o_{Fe^{3+} /Fe} = -0.036 \ V, E^o_{Fe^{2+} /Fe} = -0.439 \ V$
The value of standard electrode potential for the change,
$Fe^{3+}_{(aq)} + e^- \rightarrow Fe^{2+}_{(aq)}$ will be ........ $V$.