(i) Write the formulation for the galvantic cell in which the reaction
`Cu(s)+2Ag^+ (aq) toCu^(2+) (aq)+2Ag(s)`
Takes place . Identify the cathode and anode reactions in it.
(ii) Write Nernst eq. and calculate the emf of the following cell.
`Sn(s)//Sn^(2+)(0.04m)||H^+(0.02M)|H_2(g)|H(s)`

Explanation

(i) `Cu(s) to Cu^(2+) (aq)+2e^-` (anode)
`2Ag^(+) (aq)+2e^(-) to2Ag(s)` (At cathode)
`overlineunderline (Cu(s)+2Ag^(+) (aq) to Cu^(2+) (aq) +2Ag (s))`
Cu is acting as anode while Ag is acting as cathode.
(ii) `Sn(s) to Sn^(2+) (aq)+2e^-`
`2H^+ (aq)+2e^(-) to H_2(g)`
`overline underline(Sn(s)+2H^+ (aq)to Sn^(2+) (aq) +H_2(g))`
Nernst equation
`E_(cell)=E_(cell)^@-0.0591/2log""([Sn^(2+)])/([H^+]^2)`
`=(E_(H^+//H_2)^@-E_(Sn^(2+)//Sn)^@)-0.0591/2log""0.04/(0.02)^2`
`=[0-(0.14)]-0.0591/2log""4/100 times 100/2 times 100/2`
`=+0.14V-0.0591=0.0809 V`