Question

Among the following which statements about boiling-point elevation is not true?
I. Addition of a nonvolatile solute raises the vapor pressure of a solution. Therefore, a higher temperature will be needed to produce boiling.
II. The molal concentration of solute particles dissolved in the solvent is an important factor in determining the molal boiling-point elevation constant.
III. The identity of solute particles dissolved in the solvent is an important factor in determining the molal boiling-point elevation constant.

• A. I only
• B. II only
• C. I and III only
• D. II and III only
• E. I, II, and III

Answer 1

Answer: (E)

I, II, and III

I. Addition of a nonvolatile solute lowers the vapor pressure of a solution. Therefore, a higher temperature will be needed to produce boiling.
II. The molal concentration of solute particles dissolved in the solvent is an important factor in determining the elevation in the boiling-point. The molal boiling-point elevation constant is characteristic of solvent and is independent of the molal concentration of solute particles dissolved in the solvent.
III. The identity of solute particles dissolved in the solvent is an important factor in determining the elevation in the boiling-point. The molal boiling-point elevation constant is characteristic of solvent and is independent of the identity of solute.