Question

What type of a battery is lead storage battery? Write the anode and cathode reactions and the overall cell reaction occurring in the operation of a lead storage battery.
(b) Calucluate the potential for half-cell containing.
0.10 M `K_(2)Cr_(2)O_(7)(aq), 0.20 M Cr^(3+) (aq) and 1.0 xx 10^(-4) M H^(+) (aq)`
The half -cell reaction is
`Cr_(2)O_(7)^(2-) (aq) + 4H^(+) (aq) + 6 e^(-) to 2 Cr^(3+) (aq) + 7H_(2)O(l)`
and the standard electron potential is given as `E^(o) = 1.33V`.

Answer 1

(b) The cell reaction for the cell :
`Cr_(2)O_(7)^(2-)(aq) + 14H^(+) (aq) + 6e^(-) to 2Cr^(3+) (aq)+ 7H_(2)O(l)`
`E=E^(@)"Cell" -(0.0591)/(n) log.([Cr^(3+)]^(2))/([Cr_(2)O_(7^(2-))][H^(+)]^(14))`
`=1.33-(0.0591)/(6) log.((0.2)^(2))/(0.1 xx(1xx10^(-4))^(14))`
`=1.33 xx-(0.0591)/(6) log.4 xx 10^(55)= 1.33-(0.0591)/(6) xx 55.6021`
`=1.33 - 0.54 = 0.7823V`