Question

The ?a of a monoprotic weak acid is 0.00732. What is the percent ionization of a 0.123 M solution of this acid?

Percent ionization: %

Answer 1

Answer:- % ionisation = 21.60%

Given:-

K_a = 0.00732  

[HA]_(initial) = 0.123 M

Let the ionisation of acid HA is

  

Consider 'x' moles of acid ionizes

Now we construct ICE table

Initial	0.123 - 0 0
Change	-x - +x +x
Equilibrium	0.123-x - x x

Now, K_a is given by

...(1)

from ICE table we get,

ie   ....(2)

eq(2) is quadratic equation its roots are given by

and   

  

and

ie

and

ie

and

and

and

but 'x' is a concentration and it can't have negative value

Hence,

Therefore,

Now, % ionisation is