Practice question

Given: What is the molality of a solution containing 8 g of NaOH in 400 g of water? (Molar mass of NaOH = 40 g/mol) These values define the system as per NCERT data. Formula: Moles = 8 / 40 = 0.2 mol. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Mass of solvent = 0.4 kg. Molality = 0.2 / 0.4 = 0.5 m. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.