Exams › JEE Advanced › Chemistry

A compound H2X (molar mass 80 g/mol) is dissolved in a solvent of density 0.4 g/mL. Assuming the volume does not change on dissolving, find the molality of a 3.2 molar solution.

1. 8 m
2. 3.2 m
3. 4 m
4. 6.4 m

Correct answer: 8 m

Solution

Since volume is unchanged, 1 L of solvent (0.4 kg) holds 3.2 mol solute, but molality = 3.2/0.4 = 8 m.

Related JEE Advanced Chemistry questions

• Which of the following contains the highest number of molecules?
• An organic compound with identical empirical and molecular formulas consists of 20% carbon, 6.7% hydrogen, 46.7% nitrogen, and the remainder as oxygen. When heated, it releases ammonia and leaves behind a solid residue. This residue produces a violet color when treated with an alkaline copper sulfate solution. Identify the compound.
• Which of the following statements accurately describe a hydrogen peroxide solution with a concentration of 17 g/L?
• The total energy needed to break all three P−H bonds in PH3(g) is 954 kJ mol⁻¹. What is the energy required to break a single P−H bond?
• Which of the following represents the balanced equation for the Calvin cycle in photosynthesis, showing the conversion of carbon dioxide into glucose?
• A substance H₂X with a molecular mass of 80 g is mixed into a liquid with a density of 0.4 g/ml. If the volume remains constant during dissolution, what is the molality of a solution with 3.2 molarity?

⚔️ Practice JEE Advanced Chemistry free + battle 1v1 →