The standard reduction electrode potentials of four elements are:
$A = -0.250 \ V$,$B = -0.136 \ V$,$C = -0.126 \ V$,$D = -0.402 \ V$
The element that displaces $A$ from its compounds is:

What happens to the Gibbs free energy in a spontaneous electrochemical process?

$A$ $1.0 \ M$ solution with respect to each of the metal halides $AX_3, BX_2, CX_3$ and $DX_2$ is electrolysed using platinum electrodes. If
$E^o_{A^{3+}/A} = 1.50 \ V, \quad E^o_{B^{2+}/B} = 0.3 \ V,$
$E^o_{C^{3+}/C} = -0.74 \ V, \quad E^o_{D^{2+}/D} = -2.37 \ V.$
The correct sequence in which the various metals are deposited at the cathode is

What is cell potential and $emf$? Explain with suitable examples.

Which of the following metals does not release $H_{2(g)}$ upon reaction with acid?

The standard reduction potential for $Mg^{2+}/Mg$ is $-2.37 \ V$ and for $Cu^{2+}/Cu$ is $0.337 \ V$. The $E^{\circ}_{cell}$ for the following reaction is $Mg + Cu^{2+} \longrightarrow Mg^{2+} + Cu$