The ioisation constant of a weak electroluytes is `25 xx 10^(-6)` and the equivalent conductance of its ` 0.01M` solution is `19.6 S cm^2 eq^(-1)`. The equivalent conductance at infinited dilution of the electrolyte is ` S cm^2 sq^(-1)`. is .

Options

A. 402
B. 392
C. 306
D. 39.2

Answer

B

Explanation

`K = (c alpha^(2))/(1 - alpha) = c alpha^(2)`
`2.5 xx 10^(-5) = 0.01 alpha^(2)`
`alpha = sqrt((2.5 xx 10^(-5))/(0.01)) = 5 xx 10^(-2)`
`alpha = (Lambda^(c))/(Lambda^(oo))`
or `Lambda^(oo) = (Lambda^(c))/(alpha) = (19.6)/( 5 xx 10^-2) = 392 ohm^(-1) cm^2 mol^-1`