The degre of dissociation of weak electrolyte is inversely proportional to the same square root of concentration. What is called Ostwald's dilution law.
`alpha = sqrt((K_(a))/(c ))` As the temperature increases, degree of dissociation will increase.
`(alpha_(1))/(alpha_(2)) = sqrt((K_(a1))/(K_(a2)))` if concentration is same. `(alpha_(1))/(alpha_(2)) = sqrt((c_(2))/(c_(1)))` if acid is sam.
For two monobasic acids `HA_(1)` and `HA_(2)` at the same concentration `alpha_(1)` and `alpha_(2)` are in ratio of 1:2. `K_(a1) = 2 xx 10^(-4)`. What will be `K_(a2)` ? `8 xx 10^(-4)`, `2 xx 10^(-4)`, `4 xx 10^(-4)`, `1 xx 10^(-4)`

Options

A. `8 xx 10^(-4)`
B. `2 xx 10^(-4)`
C. `4 xx 10^(-4)`
D. `1 xx 10^(-4)`

Answer

A

Explanation

`(alpha_(1))/(alpha_(2)) = (1)/(2) = sqrt((K_(a1))/(K_(a_(2)))) rArr K_(a2) = 4K_(a1) = 8 xx 10^(-4)`