(a) What type of a battery is the lead storage battery? Write the anode and the cathode reactions and the overall reaction occuring in a lead storage battery when current is drawn from it.
(b) In the button cell, widely used in watches, the following reactions takes place:
`Zn(s)+Ag_2O(s)+H_2O(l) to Zn^(2+) (aq)+2OH^(-) (aq)`
Determine `E^@ and Delta G^@` for the reaction:

Explanation

(a) It is secondary cell
Anode reaction:
`Pb+SO_4^(2-) to PbSO_4(s)+2e^(-)`
`Cathode reaction: PbO_2+4H^+ +SO_(4)^(-) +2e to PbSO_+2H_2O`
`Net reaction: Pb+PbO_2+2H_2SO_4 to 2PbSO_4+2H_2O`
(b) `E_(cell)^@=E_(cathode)^@-E_(anode)^@ `
=0.80V-(-0.76)V
=+1.56 V
`Delta RG^@=-nFE_(cell)^@`
`=-2 times 96500 C mol^-1 times 1.56 V`
`=-301080 J mol^-1` or `-301.08KJ mol^-1`