Question

A weak acid, HA, has a `K_(a)` of `1.00xx10^(-5)`. If `0.100` mol of the acid is dissolved in 1 L of water, the percentage of the acid dissociated at equilibrium is the closed to
A. `1.0 %`
B. `99.9%`
C. `0.10%`
D. `99.0%`

Answer 1

Correct Answer - A
`alpha = sqrt((K_(a))/(C)) =sqrt((1xx10^(-5))/(0.1)) =10^(-2) =0.01`
Precentage dissociation =1.0 %