(a) What type of a battery is the lead storage battery ? Write the anode and the cathode reactions and the overall occuring in a lead storage battery when current is drawn from it.
(b) In the buttom cell, widely used in watches the following reaction take place
`Zn_((s)) + Ag_(2)O_((l)) rarr Zn^(2+)(aq) + 2Ag_((s)) + 2OH_((aq))^(-)`.
Determine `E^(@)` and `DeltaG^(@)` for the reaction.
(given : `E_(Ag^(+)//Ag)^(@) = +0.80 V , E_(Zn^(2+)//Zn)^(@) = - 0.76 V)`

Explanation

(a). Lead storage battery= it consists of a lead anode ad a grid of lead packed with lead dioxide as cathode. A solphuric acid (`38%` by mass) is used as electrolyte.
The cell reactions when the battery is in use are given below.
Anode: `Pb(s)+SO^(2-)(aq)toPbSO_(4)(s)+2e^(-)`
cathode: `underline(PbO_(2)(s)+SO_(4)^(2-)(aq)+4H^(+)(aq)+2e^(-)toPbSO_(4)(s)+2H_(2)O(l))`
`underline("over cell reaction" Pb(s)+PbO_(2)(s)+2H_(2)SO_(4)(aq)to2PbSO_(4)(s)+2H_(2)O(l))`
(b). Anode: `Zn(s)toZn^(2+)(aq)+2e^(-)`
cathode: `underline(2Ag^(+)(aq)+2e^(-)to2At(s))`
Overall cell reaction `underline(Zn(s)+2Ag^(+)(aq)toZn^(2+)(aq)+2Ag(s))`
`E_(cell)^(@)=(E_(SRP)^(0)-E_(SRP)^(0))=+0.80V-(-0.76V)=+1.56V`
`triangle_(r)G^(0)=nE^(0)F`
`triangle_(r)G^(0)=-2xx1.56Vxx96500C=-301080Jmol^(-1)=-301.080kJmol^(-1)`