Arrange the following solutions in increasing order of their concentration.

(A) 7.5 g KCl (74.5 g $mol^{-1}$) in 100 mL solution
(B) 3 g Urea (60 g $mol^{-1}$) in 1 L solution
(C) 3.6 g glucose (180 g $mol^{-1}$) in 100 mL solution
(D) 4 g NaOH (40 g $mol^{-1}$) in 1 L solution

Choose the correct answer from the options given below:

(B), (D), (C), (A)

The correct answer is Option (3) → (B), (D), (C), (A)

To arrange the solutions in increasing order of concentration, we calculate the molarity (M) of each solution.

Molarity (M) = (mass / molar mass) / volume in litres

Molarity values:

• (B) Urea → 0.05 M
• (D) NaOH → 0.10 M
• (C) Glucose → 0.20 M
• (A) KCl → 1.0067 M

Increasing order of concentration (molarity): (B) < (D) < (C) < (A)