A 0.495 M solution of nitrous acid, HNO2, has a pH of 1.83.a. Find the [H+] and the percent ionization of nitrous acid in this solution.  

Expert Answers
jeew-m eNotes educator| Certified Educator

`HNO_2 harr H^++NO_2^-`

Since `HNO_2` is not a strong acid it's ionization is not complete. So in the final mixture we have both `H^+` and `HNO_2` .

We know that;

`P_H = -log[H^+]`

`1.83 = -log[H^+]`

`[H^+] = 10^(-1.83)`

`[H^+] = 0.0148M`

So the concentration of `H^+` is 0.0148M.


We had 0.495M `HNO_2` solution. But only 0.0148M has ionized.

% of ionization `= (0.0148/0.495)xx100% = 29.9%`


So the percentage ionization of `HNO_2` is 29.9%.