At `25^(@)C` molar conductance of `0.1` molar aqueous solution of ammonium hydroxide is `9.54 ohm^(-1) cm^(2) mol^(-1)` and at infinte dilution its molar conductance is `238 ohm^(-1) cm^(2) mol^(-1)` The degree of ionisation of ammonium hydroxide at the same concentration and termperature is

Options

A. `2.080 %`
B. `20.800%`
C. `4.008%`
D. `40.800%`

Answer

C

Explanation

`alpha=(pi_(m))/(pi_(m)^(oo))=(9.54)/(238)=0.04008`
`or 4.008%`