A solution containing `1 mol` per litre of each `Cu(NO_(3))_(2), AgNO_(3),` and` Hg_(2)(NO_(3))_(2)` is being electrolyzed by using inert electrodes. The values of standard electrode potentials in volts `(` reduction potential `)` are
`Ag|Ag^(o+)=+0.80, 2Hg|Hg_(2)^(2+)=+0.79`
`Cu|Cu^(2+)=+0.34,Mg|Mg^(2+)=-2.37`.
With increasing voltage, the sequence of deposition of metals at the cathode will be

Options

A. `Ag,Hg,Cu,Mg`
B. `Mg,Cu,Hg,Ag`
C. `Ag,Hg,Cu,Mg`
D. `Cu,Hg,Ag,Mg`

Answer

a

Explanation

Higher the oxidation potential, more easily it is oxidized and faster is the deposition of metal.
Decreasing order of `E^(c-)._(o x I dation)` is `:`
`E^(c-)._(Ag|Ag^(o+)(0.80))gtE^(c-)._(2Hg|Hg_(2)^(2+))(0.79)gtE^(c-)._(Cu|Cu^(2+)(0.34))gtE^(c-)._(Mg|Mg^(2+)(-2.37))`
Hence, the sequence of deposition of metals at the cathode will `Ag, Hg, ` and `Cu`...