Why is the mole fraction of solute in a 1 molal aqueous solution around 0.0177?
Answer and explanation
Correct answer: Because 1 kg water has about 55.5 mol water
A 1 molal aqueous solution contains 1 mol of solute in 1 kg of water. Using the molar mass of water, 18 g mol−1, the solvent contains 1000/18 ≈ 55.5 mol water. Therefore, total moles are 1 + 55.5 = 56.5 mol, and the solute mole fraction is x = 1/56.5 ≈ 0.0177. Hence option A is correct; the other statements confuse volume, mass, or concentration units.
Frequently asked questions
What is the correct answer to this question?
Because 1 kg water has about 55.5 mol water
Why is this the correct answer?
A 1 molal aqueous solution contains 1 mol of solute in 1 kg of water. Using the molar mass of water, 18 g mol−1, the solvent contains 1000/18 ≈ 55.5 mol water. Therefore, total moles are 1 + 55.5 = 56.5 mol, and the solute mole fraction is x = 1/56.5 ≈ 0.0177. Hence option A is correct; the other statements confuse volume, mass, or concentration units.
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.
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