What is the pH of the resulting solution when equal volumes of 0.1 M NaOH and 0.01 M HCl are mixed?

• 12.65

• 2.0

• 7.0

• 1.04

A.

12.65

When equal volumes of acid and base are mixed then resulting solution become alkaline if the concentration of base is taken high.
Let normality  of the solution after mixing 0.1 M
NaOH and 0.01 M HCl is N.
therefore,   N₁V₁ - N₂V₂ = NV
or   0.1 x 1 - 0.01 x 1 = N x 2
Since normality, of NaOH, is more than that of HCl. Hence, the resulting solution is alkaline.
Or
[OH^-] = N = 0.09/2 = 0.045 N
Or pOH = - log (0.045) = 1.35
therefore, pH = 14-pOH
= 14 - 1.35 = 12.65