3. In one molal solution that contains 0.5 mol of solute, there is (A) 500 g of solvent (B) 100 mL of solvent (C) 1000 g of solvent (D) 500 mL of solvent 4. The mixture that forms maximum boiling azeotrope at a specific composition is (A) Water + Nitric acid (B) Ethanol + water
Answer (1)
Let's break down the questions one by one:
Question 3: In a one molal (1 m) solution, the definition of molality is the number of moles of solute per kilogram of solvent. So, if there is 0.5 mol of solute in a one molal solution, it means:
Molality (m) = 1 m = 1 mole of solute per 1 kg (1000 g) of solvent.
Therefore, if we have 0.5 mol of solute, we still need 1000 g of solvent to maintain the same molality.
Hence, the correct option is (C) 1000 g of solvent .
Question 4: Azeotropes are mixtures that have the same composition in liquid and vapor phase and boil at a constant temperature, similar to a pure substance. A maximum boiling azeotrope boils at a higher temperature than either of its components.
Water + Nitric acid is known to form a maximum boiling azeotrope at a specific composition.
Ethanol + water forms a minimum boiling azeotrope.
Therefore, the correct option is (A) Water + Nitric acid .
