Question

The degree of dissociation of 1.0 M weak acid, HA 0.5. If 2m of 1.0M HA solution is diluted to 32 ml,the degree of dissociation of the acid and H3O+ concentration in th resulting solution will respectively?

Answer 1

The degree of dissociation of 1.0 M weak acid, HA 0.5. If 2m of 1.0M HA solution is diluted to 32 ml,the degree of dissociation of the acid and H3O+ concentration in th resulting solution will respectively?

Explanation:

Given,

α=0.5%=0.005 and C=0.1 M

The expression for the degree of dissociation is

α= √K a/C

0.005= √K a/0.1

​

​

K a =2.5×10 −6

When the solution is diluted, the molarity of the solution is given by the following expression.

M 1 V 1=M 2V 2

​

or 2×1=32×M 2

​ Therefore, M 2 = 1/16

For this diluted solution, α=√Ka/ C

=0.632%.

The hydrogen ion concentration is [H

+ ]=cα=

1/16×0.00632=3.955×10 −4