Question
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
Solution
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
