Electrochemical Cells

The standard electrode potential (E°) values of A⁺/A, B⁺/B, C⁺/C and D⁺/D are 2.19 V, 1.87 V, -2.93 V and -1.7 V respectively. The correct decreasing order of reducing power of the metal is

If standard reduction potential of three metals, A, B and C are -0.5 V, +1.2 V and -1.5 V respectively, then the order of reducing power of the metals will be

Standard Gibbs energy ($\Delta_r G^\circ$) of the reaction Mg(s) + Cu$^{2+}$(aq) $\rightleftharpoons$ Mg$^{2+}$(aq) + Cu(s); E$^\circ_{cell}$ = 2.71 V at 298 K is

Given the standard electrode potentials, Zn²⁺/Zn = -0.76 V, Al³⁺/Al = -1.66 V, Ca²⁺/Ca = -2.87 V, Na⁺/Na = -2.71 V, Mg²⁺/Mg = -2.36 V. The correct order of reducing power of these metals is