Calculate the pH of a solution on mixing 0.1 M (50 mL) Ch3cooh and 0.1M(50 mL) Naoh
Ka= 0.00005

here

Explanation:

Ka=Cx^2/1-x

Ka =1.8 x 10^-5

C = 0.1

If we consider x is negligible ie., x~0

Then x=(Ka/c)^0.5

={1.8 x 10^-5/0.1)^0.5 =0.01342

So concetration of H+ ion =Cx

=0.1 x 0.01342 =0.001342

pH=- log(0.001342) =2.87

However it is only an approximate method. Without using approximation, if we solve equation

Ka =Cx^2/1-x , for value of 'x', where C=0.1 then

We get x = 0.01273

So concetration of H+ ion = Cx

=0.1 x 0.01273 =0.001273

pH = - log (0.001273)

= 2.89.