Question

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

Answer 1

Correct Answer - B
The degree of ionisation `(alpha)` of ammonium hydrox-ide at the same temperature and concentration is given as follows:
`alpha=(Lambda_(m)^(c))/(Lambda_(m)^(oo))`
`= (9.54 ohm^(-1)cm^(2)mol^(-1))/(238 ohm^(-1)cm^(2)mol^(-1))`
`= 0.04008`
Therefore, percentage ionisation will be `= 0.04008 xx 100% = 4.008%`