Answer:
To obtain the pH of 8.0, the concentration of NaOCl needs to be 0.9 M in the 0.3 M HOCl solution
Explanation:
This problem can be solved by Henderson-Hasselbalch equation, which gives relation between the concentration of acid, its salt, pKa and the pH of the solution. This equation is given as,
[tex]pH=-log(K_a)+log\frac{[NaOCl]}{[HOCl]}[/tex]
By placing the known variables in the above equation we get,
[tex]8=-log(3\times10^{-8})+log\frac{[NaOCl]}{0.3}[/tex]
[tex]8-7.52=log\frac{[NaOCl]}{[0.3]}[/tex]
[tex]10^{0.48}=\frac{[NaOCl]}{0.3}[/tex]
[tex][NaOCl]=10^{0.48}\times{0.3}[/tex]
[tex][NaOCl]=0.9 M[/tex]
The above calculations show that the required concentration of NaOCl is 0.9 M.
