What is the ph of a solution of 0.20 m hno2 containing 0.10 m nano2 at 25°c

This is an incomplete question, here is a complete question.

What is the pH of a solution of 0.20 M HNO₂ containing 0.10 M NaNO₂ at 25°C, given Ka of HNO₂ is 4.5 × 10⁻⁴?

Answer : The pH of the solution is, 3.05

Explanation : Given,

for HNO₂ = 4.5 × 10⁻⁴

Concentration of = 0.20 M

Concentration of = 0.10 M

First we have to calculate the value of .

The expression used for the calculation of is,

Now put the value of in this expression, we get:

Now we have to calculate the pH of the solution.

Using Henderson Hesselbach equation :

Now put all the given values in this expression, we get:

Therefore, the pH of the solution is, 3.05

the answer is b. dilution