The molar conductance of ammonium hydroxide solution of concentration 0.1 M, 0.01M and 0.001 M are 3.6, 11.3 and `34.0 ohm^(-1)cm^(2)mol^(-1)` respectively. Calculate the degree of dissociation of `NH_(4)OH` at these concentrations. Molar conductance at infinite dilution for `Nh_(4)OH` is 271.1 `ohm^(-1)cm^(2)mol^(-1)`.

Explanation

Degree of dissociation is given as `alpha =(Lambda^(c))/(Lambda^(@))` where `Lambda^(c)` is the molar conductance at concentration C and `Lambda^(@)` is the molar conductance at infinite dilution .
(i) At ` C = 0.1 M , Lambda^(c) = 3.6`,
`Lambda^(@) = 271.1`
`therefore alpha = (3.6)/(271.1) = 0.013`
i.e, 1.3 % dissociated .
(ii) At C = `0.001 M , Lambda^(c) = 34.0 , Lambda^(@) = 271.1`
`therefore alpha = (34.0)/(271.1) = 0.125`
i.e., 12.5% dissociated.