Answer:
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.
