Question

A weak electrolyte having the limiting equivalent conductance of 400 S `cm^(2)g`. `"equivalent"^(-1)` at 298 K is 2% ionized in its 0.1N solution. The resistance of this solution (in ohms) in an electrolytic cell of cell constant 0.4 `cm^(-1)` at this temperature is:-
A. 200
B. 300
C. 400
D. 500

Answer 1

Correct Answer - D
`alpha=(wedge_(m))/_(wedge_(oo))`
`wedge_(oo)=400S" "cm^(2)g" "eq^(-1)`
`wedge_(m)=wedge_(oo)xxalpha=400xx(2)/(100)=8`
`wedge_(m)=(kxx1000)/(C)`
`k=(1)/(R)xx`cell constant
`wedge_(m)=(1)/(R)xx`cell constant`xx(1000)/(C)`
`R=("cell constant")/(wedge_(m)xxC)xx1000`
`R=(0.4xx1000)/(8xx0.1)=500ohm`