Question

Version 2 sider the phase diagram of an aqueous solution and that for pure water. Which of the following statements are true? A) The line representing freezing for the solution phase diagram is shifted to the left / of that for pure water. (B) The line representing freezing for the solution phase diagram is shifted to the right of that for pure water. C) The line representing boiling for the solution phase diagram is shifted to the left of that for pure water. D) The line representing boiling for the solution phase diagram is shifted to the right of that for pure water. E) Answers A and C are correct F) Answers B and D are correct G) Answers A and D are correct H) Answers B and C are correct 6) Which of the following aqueous solutions will have the highest freezing point? A) 0.250 m CH CH OH B) 0.180 m AlPO4 C) 0.060 m Al(SO4)3 D) 0.095 m (NH4)2P04 E) 0.100 m MgCl2

Answer 1

5.) This is a colligative property problem.

Adding solute to a solvent, decreases the freezing point of the solution than the freezing point of the pure solvent. That is called Freezing Point Depression.

  Adding solute to a solvent, increases the boiling point of the solution than the boiling point of the pure solvent. And that is called Elevation of Boiling Point.

Therefore the Statements A and D are TRUE.

Freezing line of aq. som boiling, line of Pure water a Freezing - Line of pure water boiling line of aq. sol. NOTH 0 on 5 2 2 5

6.) Aqueous solution of (A) 0.250 m CH₃CH₂OH (Ethanol) will have the highest freezing point. The depression of freezing point depends on the number of solute particles in the solution. Ethanol does not dissociate in aqueous solution. But all the other solutes, mentioned there, are ionic and dissociates in aqueous solution to give the constituent ions. Therefore the number of particles in these solutions shall be greater than that of the Ethanol solution. Hence the freezing point of those solutions will be less than the freezing point of the Ethanol solution, i.e. option A is CORRECT.

Hope that will help :-)

Freezing line of aq. som boiling, line of Pure water a Freezing - Line of pure water boiling line of aq. sol. NOTH 0 on 5 2 2 5