(a) Calculate the emf of the cell in which the following reaction takes place
`Ni(S) + 2Ag^(+)(0.002M) rarr Ni^(2+)(0.160M) + 2Ag(S)`
Given that `E_(cell)^(circ)= 1.05V`
(b) A galvanic cell after use is recharged by passing current through it. What type of cell is it? Give an example.

Explanation

(a) Applying Nernst Equation,
`E_(cell) = E^(circ)_(cell) - 0.0591/n log[Ni^(2+)]/[Ag^(+)]^(2)`
`= 1.05 - 0.02955 log (0.160)/(0.002)^(2) = 1.05 - 0.02955log(0.16)/(0.002)^(2)`
`= 1.05 - 0.02955log 4 xx 10^(4) = 1.05 - 0.02955(log10000 + log 4)`
`= 1.05 - 0.02955(4 +0.6021) = 0.914V`
(b) Secondary cell
e.g. Lead storage battery