5 litre solution of 0.4M `CuSO_((aq))` is electrolysed using Cu electrode. A current of 482.5 ampere of passed for 4 minute. The concentrations of `CuSO_4` left in solution is

Options

A. 0.16 M
B. 0.32 M
C. 0.34 M
D. 0.40 M

Explanation

Let us suppose `K_1` and `K_2` are the specific conductance of solutions 'A' and 'B' repectively and cell constant is 'y'. We know that, Specific conductance = Conductance `xx` Cell constant
(A), `k_1` = `1/50xxy` For (B), `k_2` = `1/100xxy`
When equal volume of (A) and (B) are mixed, the volume becomes double. then,
Specific conductance of mixture = `(k_1+k_2)/2`
`:. (k_1 + k_2)/2=1/Rxxy` `1/2[y/50+y/100]=1/Rxxy`
`1/100+1/200=1/R`
R=`200//3`=66.66 ohm