JEE Main · 2023 · 12 Apr 2023 · Shift 1 · Some Basic Concepts of Chemistry

An analyst wants to convert. 1 L HCl of

pH = 1

to a solution of HCl of pH 2 . The volume of water needed to do this dilution is

____

mL. (Nearest Integer)

Answer: 9000

Solution

At pH

1

the hydrogen-ion concentration is

0.1 M

and at pH

2

it is

0.01 M

. Dilution does not change the amount of acid, so

M_{1} V_{1} = M_{2} V_{2}

0.1 \times 1 = 0.01 \times V_{2} ⟹ V_{2} = 10 L

The water to be added is

V_{2} - V_{1} = 10 - 1 = 9 L

. The volume of water needed is 9000 mL.

JEE Main · 2023 · 12 Apr 2023 · Shift 1 · Integer answer