### Neet Solved Paper 2013 Question 6

##### Question: At $ 25{}^\circ C $ molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is 9.54 $ oh{m^{\text{-1}}}c{m^{2}} $ $ mo{l^{\text{-1}}} $ and at infinite dilution its molar conductance is $ 238,oh{m^{\text{-1}}} $ $ c{m^{2}} $ $ mo{l^{\text{-1}}}. $ The degree of ionization of ammonium hydroxide at the same concentration and temperature is

#### Options:

A) 2.080%

B) 20.800%

C) 4.008%

D) 40.800%

## Show Answer

#### Answer:

Correct Answer: C

#### Solution:

Given, molar conductance at 0.1 M concentration,

$ {\lambda_c}=9.54{{\Omega }^{-1}}cm^{2}mo{l^{-1}} $ Molar conductance at infinite dilution,

$ \lambda _c^{\infty }=238{{\Omega }^{-1}}cm^{2}mo{l^{-1}} $

We know that, Degree of ionization,

$ \alpha =\frac{\lambda _c^{{}}}{\lambda _c^{\infty }}\times 100 $ $ =\frac{9.54}{238}\times 100=4.008% $