Question

Two HCl solutions A and B have concentrations of 0.5 N and 0.1 N respectively. The volume of solutions A and B needed to make 2 L of 0.2 N HCl are

(a)  1.5 L of A + 0.5 L of B

(b)  1.0 L of A + 1.0 L of B

(c)  0.75 L of A + 1.25 L of B

(d)  0.5 L of A + 1.5L of B

Answer 1

Correct option  (d) 0.5 L of A + 1.5L of B

Explanation:

N₁V₁ + N₂V₂ = NV

Let vol. of A be x litres, therefore vol. of B is (2 – x) litres.

Using formula we get, 0.5 × x + (2 – x) × 0.1 = 0.2×2

⇒ 0.5x + 0.2 – 0.1x = 0.4

⇒ 0.4x = 0.2 ⇒ x = 0.5

Vol. of A is 0.5 litres, Vol. of B is 2 – 0.5 = 1.5 litres