Calculate the ph in an aqueous 0.120 m nitrous acid solution.

-  pH is 2.14.

Solution:- Nitrous acid, is a weak acid so first of all we solve for and then figure out the pH.

the equation is written as:

Initial concentration for the acid is given as 0.120 M. Let's say the change in concentration is x. Then the equilibrium concentrations would be as:

=

=

Ka for nitrous acid is and the equilibrium expression for this would be written as:

Let's plug in the values in it.

To make the calculations easy we could ignore for the bottom and the expression becomes:

On cross multiply:

On taking square root to both sides:

So,

Now we could calculate the pH using the pH formula:

pH = 2.14

So, the pH of 0.120M nitrous acid is 2.14.

it's all four options.