InterviewSolution
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InterviewSolution
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A solution containing one mole per litre of each `Cu(NO_(3))_(2), AgNO_(3), Hg_(2)(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 V, HG_(2)^(2+)//Hg = +0.79 V` `Cu^(+)//Cu = +0.34 V, Mg^(2+)//Mg = -2.37 V` With increasing valtage, the sequence of deposition of metals on the cathode will beA. `Cu, Hg, Ag`B. `Ag, Hg, Cu, Mg`C. `Ag, Hg, Cu`D. `Mg, Cu, Hg, Ag` |
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Answer» Correct Answer - C The higher the reduction potential, reater the tendency to get reduced. Since reduction potentials of the ions are in the order : `Ag^(+) gt Hg_(2)^(2+) gt Cu^(2+) gt Mg^(2+)` We expect the second option to be correct but `Mg^(2+)` is never reduced in aqueous solution as its reaction potential is much lower than that of water `(-0.83 V)`. Therefore, the correct sequence of deposition of the metals will be: Ag, Hg, Cu. |
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