The standard potentials of Ag+/Ag, Hg22+/2Hg, Cu2+/Cu and Mg2+/Mg electrodes are 0.80,0.79, 0.34 and -2.37 V, respectively. An aqueous solution which contains one mole per litre of the salts of each of the four metals is electrolyzed. With increasing voltage, the correct sequence of deposition of the metals at the cathode is

Question

The standard potentials of Ag+/Ag, Hg22+/2Hg, Cu2+/Cu and Mg2+/Mg electrodes are 0.80,0.79, 0.34 and -2.37 V, respectively. An aqueous solution which contains one mole per litre of the salts of each of the four metals is electrolyzed. With increasing voltage, the correct sequence of deposition of the metals at the cathode is (A) Ag, Hg, Cu, Mg (B) Cu,Hg,Ag only (C) Ag, Hg, Cu only (D) Mg,Cu,Hg,Ag

Tardigrade Admin · Accepted Answer

More the reduction potential, more is the deposition of metals at cathode. Cation having

E^{0}

value less than

- 0.83 V

(reduction potential of

H_{2} O

) will not deposit from aqueous solution. Hence correct order of A deposition of the metal at the cathode is

A g > H g > C u

$A g, H g, C u, M g$

$C u, H g, A g$ only

$A g, H g, C u$ only

$M g, C u, H g, A g$

More the reduction potential, more is the deposition of metals at cathode. Cation having $E^{0}$ value less than $- 0.83 V$ (reduction potential of $H_{2} O$ ) will not deposit from aqueous solution. Hence correct order of A deposition of the metal at the cathode is
$A g > H g > C u$

Ag,Hg,Cu,Mg

Cu,Hg,Ag only

Ag,Hg,Cu only

Mg,Cu,Hg,Ag

More the reduction potential, more is the deposition of metals at cathode. Cation having E0 value less than −0.83V (reduction potential of H2​O) will not deposit from aqueous solution. Hence correct order of A deposition of the metal at the cathode is Ag>Hg>Cu

$A g, H g, C u, M g$

$C u, H g, A g$ only

$A g, H g, C u$ only

$M g, C u, H g, A g$

More the reduction potential, more is the deposition of metals at cathode. Cation having $E^{0}$ value less than $- 0.83 V$ (reduction potential of $H_{2} O$ ) will not deposit from aqueous solution. Hence correct order of A deposition of the metal at the cathode is
$A g > H g > C u$