Which of the following solutions will have pH close to 1.0 ?

Options

A. 100 mL of `(M//10)` HCl + 100 mL of `(M//10)` NaOH
B. 55 mL of `(M//10)` HCl + 45 mL of `(M//10)` NaOH
C. 10 mL of `(M//10)` HCl + 90 mL of `(M//10)` NaOH
D. 75 mL of `(M//5)` HCl + 25 mL of `(M//5)` NaOH

Answer

D

Explanation

75 mL m/5 HCl = 15 m molHCl
25mL M/5 NaOH = 5 m molNaOH
After neutralization, `10 m mol HCl` will be remaining in 100 mL of solution.
Molarity of HCl in the final solution = 10/100 = 0.10
`pH = -log[H^(+)] = -log(0.10) = 1`