A solution of NaOH has a molarity of 1 M and a density of 1.04 g/mL. What is its molality? (Molar mass: NaOH = 40 g/mol)
Mass of 1 L solution = 1000 × 1.04 = 1040 g. Mass of NaOH = 1 × 40 = 40 g. Mass of water = 1000 g = 1 kg. Molality = 1/1 = 1 m.
Ref: NCERT Class 11 Chemistry > Chapter 1: Some Basic Concepts of Chemistry > Topic: Reactions in Solutions and Mass Percentage and Numericals