If molality is 0.5 mol/kg and the solvent mass is 2 kg, how many moles of solute are present?
Answer and explanation
Correct answer: 1 mole
Molality is defined as moles of solute divided by the mass of solvent in kilograms: m = n / mass of solvent. Rearranging gives n = m × mass of solvent. Hence n = 0.5 mol kg⁻¹ × 2 kg = 1 mol, so option A is correct. The kilogram units cancel. Options B and C are the individual given values, while 4 mol comes from an incorrect calculation.
Frequently asked questions
What is the correct answer to this question?
1 mole
Why is this the correct answer?
Molality is defined as moles of solute divided by the mass of solvent in kilograms: m = n / mass of solvent. Rearranging gives n = m × mass of solvent. Hence n = 0.5 mol kg⁻¹ × 2 kg = 1 mol, so option A is correct. The kilogram units cancel. Options B and C are the individual given values, while 4 mol comes from an incorrect calculation.
Which subject and chapter does this question cover?
This is a Class 11 Chemistry question. Chapter: Chapter 01: Solutions.
