The question is incomplete, here is the complete question:
Calculate the pH at 25°C of a 0.39 M solution of sodium hypochlorite NaClO. Note that hypochlorous acid HClO is a weak acid with a pKa of 7.50. Round your answer to 1 decimal place.
<u>Answer:</u> The pH of the solution is 10.4
<u>Explanation:</u>
We are given:
Molarity of sodium hypochlorite = 0.39 M
of HClO = 7.50
We know that:
of HClO =
To calculate the base dissociation constant for the given acid dissociation constant, we use the equation:
where,
= Ionic product of water =
= Acid dissociation constant =
= Base dissociation constant
Putting values in above equation, we get:
The chemical equation for the reaction of hypochlorite ion with water follows:
<u>Initial:</u> 0.39
<u>At eqllm:</u> 0.39-x x x
The expression of for above equation follows:
Putting values in above equation, we get:
Neglecting the negative value of 'x' because concentration cannot be negative
To calculate the pOH of the solution, we use the equation:
We are given:
Putting values in above equation, we get:
To calculate pH of the solution, we use the equation:
Hence, the pH of the solution is 10.4