Question

100 mL HCl solution having pH = 1 is diluted to 250 mL. The pH of final solution is

(1) 1

(2) 1.4

(3) 1.7

(4) 2

Answer 1

Correct option is : (2) 1.4

Initial concentration = 10^–1 M

Initial volume = 100 mL

Final volume of solution = 250 mL

On dilution, M₁V₁ = M₂V₂

100 × 10^–1 = M × 250

\(\frac{10}{250} = \text{M}_f\)

\(\frac{1}{25} = \text{M}_f\)

4 × 10^–2 = M_f

pH = –log[H⁺]

= –log 4 × 10^–2

= 1.4