(a) A cell is prepared by dipping a zinc rod in 1M zinc sulphate solution and a silver electrode in 1M silver nitrate solution. The standard electrode potential given :
`E^(@)Zn_(2+1//Zn) = -0.76V, E^(@)A_(g+//)A_(g) = +0.80V`
What is the effect of increase in concentration of `Zn^(2+) " on the " E_(cell)` ?
(b) Write the products of electrolysis of aqueous solution of NaCI with platinum electrodes.
(c) Calculate e.m.f. of the following cell at 298 K:
`"Ni(s)"//"Ni"^(2+)(0.01M)////"Cu"^(2+)(0.1M)//"Cu(s)"`
`["Given"E_(Ni2+//Ni)^(@) = -0.025 V E_(Cu2+//Cu)^(@) = +0.34V]`
Write the overall cell reaction.

Explanation

(a) `E_(cell) " decreases."`
(b) `"Anode" : CI_(2)uarr`
`"Cathode" : H_(2)uarr`
(c) `Cu^(2+)(aq) + Ni(s) to Ni^(2+)(aq) + Cu(s)`
`E_(cell)^(@) = E_("cathode")^(@) - E_("anode")^(@)`
`E_(cell)^(@) = 0.34-(-0.25)`
`E_(cell)^(@) =0.59V`
`E_(cell)^(@) =E_(cell)^(@)-(2.303RT)/(nF) "log" ([Ni^(2+)])/([Cu^(2+)])`
`E_(cell)^(@) = 0.59 - (059)/(2)"log" ([0.01])/([0.1])`
`E_(cell) =0.6195V`