Question

Acetic acid is 5% ionised in its decimolar solution. Calculate the dissociation constant of acid.

Answer 1

Ionisation constant Ka = a² × c(1-a)

where a is the degree of dissociation

c is the concentration

Here a= 5% = 0.05

c = 0.1m

Substituting the values we get,  

Ka = 1.24 × 10⁻³

Answer 2

a=5/100

C=1/10

Ka=a^2 C

=25/100 ×1/10

=2.5 × 10^-4