Question

The limiting molar conductivities of HCl, `CH_(3)COONa` and NaCl are respectively 425, 90 and 250 mho `cm^(2)mol^(-1)` at `25^(@)C`.t he molar conductivity of 0.1 M `CH_(3)COOH` solution is 7.8 mho `cm^(2)mol^(-1)` at the same temperature. The degree of dissociation of 0.1 M acetic acid solution at the same temperature is
A. `0.10`
B. `0.02`
C. `0.15`
D. `0.03`

Answer 1

Correct Answer - B
`wedge_(CH_(3)COOH)^(@)=wedge_(CH_(3)COONa)^(@)+wedge_(HCl)^(@)-wedge_(NaCl)^(@)`
`=90+425-125=390" mho "cm^(2)mol^(-1)`
`alpha=(wedge_(m)^(@))/(wedge_(m)^(@))=(7.8)/(390)=.02`