JEE Main 2024 Chemistry question
Molality (m) of 3 M aqueous solution of NaCl is: (Given: Density of solution = 1.25 g mL⁻¹, Molar mass in g mol⁻¹: Na-23, Cl-35.5)
Answer: (B)
Solution
1 L of solution weighs 1250 g and contains 3 × 58.5 = 175.5 g NaCl, so 1074.5 g water: m = 3/1.0745 = 2.79 mol kg⁻¹.