A solution containing one mole per litre of each Cu ( NO 3)2, AgNO 3, Hg 2( NO 3)2 and Mg ( NO 3)2, is being electrolysed by using inert electrodes. The values of standard electrode potentials in volts (reduction potentials) are Ag + / Ag =+0.80, Hg 22+ / 2 Hg =+0.79, Cu 2+ / Cu =+0.34, and Mg 2+ / Mg =-2.37. With increasing voltage, the sequence of deposition of metals on the cathode will be

Question

A solution containing one mole per litre of each Cu ( NO 3)2, AgNO 3, Hg 2( NO 3)2 and Mg ( NO 3)2, is being electrolysed by using inert electrodes. The values of standard electrode potentials in volts (reduction potentials) are Ag + / Ag =+0.80, Hg 22+ / 2 Hg =+0.79, Cu 2+ / Cu =+0.34, and Mg 2+ / Mg =-2.37. With increasing voltage, the sequence of deposition of metals on the cathode will be (A) Ag , Hg , Cu , Mg (B) Mg , Cu , Hg , Ag (C) Ag , Hg , Cu (D) Cu , Hg , Ag

Tardigrade Admin · Accepted Answer

A cation having highest reduction potential will be reduced first and so on. However,

M g^{2 +}

in aqueous solution will not be reduced

(E_{M g^{2 +} / M g}^{\circ} < E_{H_{2} O / \frac{1}{2}} H_{2} + O H^{-})

Instead water would be reduced in preference.

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

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

$A g, H g, C u$

$C u, H g, A g$

A cation having highest reduction potential will be reduced first and so on. However, $M g^{2 +}$ in aqueous solution will not be reduced
$(E_{M g^{2 +} / M g}^{\circ} < E_{H_{2} O / \frac{1}{2}} H_{2} + O H^{-})$
Instead water would be reduced in preference.

Ag,Hg,Cu,Mg

Mg,Cu,Hg,Ag

Ag,Hg,Cu

Cu,Hg,Ag

A cation having highest reduction potential will be reduced first and so on. However, Mg2+ in aqueous solution will not be reduced (EMg2+/Mg∘​<EH2​O/21​​H2​+OH−) Instead water would be reduced in preference.

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

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

$A g, H g, C u$

$C u, H g, A g$

A cation having highest reduction potential will be reduced first and so on. However, $M g^{2 +}$ in aqueous solution will not be reduced
$(E_{M g^{2 +} / M g}^{\circ} < E_{H_{2} O / \frac{1}{2}} H_{2} + O H^{-})$
Instead water would be reduced in preference.