If 0.2 mol of solute is dissolved in 500 g of solvent, what is the molality?
Answer and explanation
Correct answer: 0.4 mol kg⁻¹
Molality is calculated using the mass of solvent, not the total mass or volume of the solution. First convert 500 g of solvent into kilograms: 500 g = 0.500 kg. Then apply m = moles of solute / kilograms of solvent. Thus m = 0.2/0.5 = 0.4 mol kg⁻¹. Therefore, option C is correct. The solute amount is already given in moles, so no further conversion is required.
Frequently asked questions
What is the correct answer to this question?
0.4 mol kg⁻¹
Why is this the correct answer?
Molality is calculated using the mass of solvent, not the total mass or volume of the solution. First convert 500 g of solvent into kilograms: 500 g = 0.500 kg. Then apply m = moles of solute / kilograms of solvent. Thus m = 0.2/0.5 = 0.4 mol kg⁻¹. Therefore, option C is correct. The solute amount is already given in moles, so no further conversion is required.
Which subject and chapter does this question cover?
This is a Class 11 Chemistry question. Chapter: Some Basic Concepts of Chemistry. Topic: Mole concept and molar mass.
