Question

The strength of elctrolytes is expressed in terms of degree of dissociation `alpha` For strong electrolyte `alpha` is close to one and for weak electrolytes `alpha` is quite small. According to Ostwald Dilution Law `alpha=sqrt((K)/(C))`
For an acid `[H^(+)] = sqrt(K_(a)C)`
For a base `[OH^(-)] =sqrt(K_(b)C`
The relative strengths of acids or bases can be compared in terms of the square roots of their `K_(a) " or " K_(b)` values.
A monoprotic acid in 0.1 M solution ionises to 0.001 % . Its ionisation constant is :
A. `1.0 xx 11^(-3)`
B. ` 1.0 xx 10^(-6)`
C. ` 1.0 xx 10^(-8)`
D. `1.0 xx 10^(-11)`

Answer 1

Correct Answer - D
`K_(a) =Calpha^(2) =0.1 xx (1xx 10^(-5))^(2) =10^(-11)`