Question

in 10ml ; pH=4 solution 990ml of .2M NaCl solution is added the pH of resulting solution will be??

Answer 1

NaCl is a salt. So it will not contribute to pH of the solution.

Volume of the solution = 10 ml
pH= 4
- log [H⁺] = 4
[H⁺] = A.log (-4)
= 1 x 10^-4
Volume of the new solution = Volume of the original solution + volume of the added NaCl
= 10 + 990 = 1000 ml
[H⁺] of the new solution = [H⁺] of the original solution + [H⁺] of the NaCl solution
= 1 x 10^-4 + 0 = 1 x 10^-4
Molarity of the new solution = ​1 x 10^-4 / 1000 = 1 x 10^-7
pH= -log [H⁺]
= - log ​1 x 10^-7
= 7