Home
Class 12
CHEMISTRY
Freezing point lowering expression is ...

Freezing point lowering expression is
`DeltaT_(f)=K_(f)m` (molality)
Which of the following assumptions are considered for the validity of above equation ?

A

The solution is dilute

B

The `DeltaH_(f)` (latent heat of fusion of solvent) is independent of temperature between the actual and normal freezing point.

C

The solid-phase consists of pure solvent when solution is allowed to cool

D

`DeltaT_(f)` is not equal to `3K_(f)` for `3 "mol" :^(-1)` solution

Text Solution

Verified by Experts

Since intermolecular forces between solvent molecules are involved, so `DeltaH` of solution and solvent is almost identical.
Promotional Banner

Topper's Solved these Questions

  • SOLUTIONS

    RESONANCE|Exercise Advabced Level Problems (PART-2)|35 Videos

  • SOLUTIONS

    RESONANCE|Exercise EXERCISE-3(PART-3)|30 Videos

  • SOLUTION AND COLLIGATIVE PROPERTIES

    RESONANCE|Exercise PHYSICAL CHEMITRY (SOLUTION & COLLIGATIVE PROPERTIES)|52 Videos

  • STEREOISOMERISM

    RESONANCE|Exercise EXERCISE (PART III : PRACTICE TEST-2 (IIT-JEE (ADVANCED PATTERN))|22 Videos

Similar Questions

Explore conceptually related problems

Which of the following aqueous molal solution have highest freezing point

Molal freezing point depression constant (K_(f)) may be calculated from the following thermodynamically derived equation

The Rast method, one of the older techniques for finding the molecular mass of an unknown, measures the freezing point depression of solution in camphor. Camphor is used because its freezing point is very sensitive to added solution solute (It has highest K_(f)) . A solution of 2.342 g of an unknown substancein 49.88 g of camphor freezes at 441.2 K . If K_(f) for camphor is 40.0 Kg mol^(-1) , calculate the molecular mass of the unknown. Strategy: Find the molality of the solution from the freezing point of the pure camphor, the freezing point of the solution and the value of K_(f) by using the relationship DeltaT_(f)=K_(f)m . From the molality, find the no. of moles of solute in given mass of solvent. Finally find the molar mass (Melting point of pure camphar is 453.0 K)

A system of greater disorder of molecules is more probable. The disorder of molecules is reflected by the entropy of the system. A liquid vapourizes to form a more disordered gas. When a solute is present, there is additional contribution to the entropy of the liquid due to increased randomness. As the entropy of solution is higher than that of pure liquid, there is weaker tendency to form the gas. Thus, a solute (non-volatile) lowers the vapour pressure of a liquid, and hence a higher boiling point of the solution. Similarly, the greater randomness of the solution opposes the tendercy to freeze. In consequence, a lower temperature must be reached for achieving the equilibrium between the solid (frozen solvent) and the solution. The elevation in boiling point (DeltaT_(b)) and depression in freezing point (DeltaT_(f)) of a solution are the colligative properties which depend only on the concentration of particles of the solute and not their identity. For dilute solutions, (DeltaT_(b)) and (DeltaT_(f)) are proportional to the molarity of the solute in the solution. A liquid possessing which of the following characteristics will be most suitable for determining the molecular mass of a compound by cryoscopic measurements?

For an ideal solution containing a non-volatille solute, which of the following expression is correct represented? where m is the molality of the solution and K_(b) is molal elevation constant.

A system of greater disorder of molecules is more probable. The disorder of molecules is reflected by the entropy of the system. A liquid vapourizes to form a more disordered gas. When a solute is present, there is additional contribution to the entropy of the liquid due to increased randomness. As the entropy of solution is higher than that of pure liquid, there is weaker tendency to form the gas. Thus, a solute (non-volatile) lowers the vapour pressure of a liquid, and hence a higher boiling point of the solution. Similarly, the greater randomness of the solution opposes the tendercy to freeze. In consequence, a lower temperature must be reached for achieving the equilibrium between the solid (frozen solvent) and the solution. The elevation in boiling point (DeltaT_(b)) and depression in freezing point (DeltaT_(f)) of a solution are the colligative properties which depend only on the concentration of particles of the solute and not their identity. For dilute solutions, (DeltaT_(b)) and (DeltaT_(f)) are proportional to the molarity of the solute in the solution. Dissolution of a non-volatile solute into a liquid leads to

RESONANCE-SOLUTIONS-Advabced Level Problems (PART-1)
  1. A liquid is in equilibrium with its vapour at its boiling point. On av...

    Text Solution

    |

  2. On the basic intermolecular force predict the correct order of decre...

    Text Solution

    |

  3. During depression of freezing point in a solution, the following are i...

    Text Solution

    |

  4. Which of the following liquid pairs shows a postive deviation from Rao...

    Text Solution

    |

  5. The relationship between osmotic pressure at 273 K when 10 g glucose (...

    Text Solution

    |

  6. Calculate the amount of ice that will separate out on cooling containi...

    Text Solution

    |

  7. Which is//are true about ideal solutions ?

    Text Solution

    |

  8. Freezing point lowering expression is DeltaT(f)=K(f)m (molality) W...

    Text Solution

    |

  9. At 35^(@)C, the vapour pressure of CS(2) is 512mmHg. And of acetone is...

    Text Solution

    |

  10. Which of the following concentration factors can be calculated if the ...

    Text Solution

    |

  11. Consider following solutions : I: 1M aqueous glucose solution II: 1M...

    Text Solution

    |

  12. Which is//are correct statement(s) ?

    Text Solution

    |

  13. At 40^(@)C, vapour pressure in Torr of methanol nd ethanol solution is...

    Text Solution

    |

  14. Which one of the following given below concerning properties of solut...

    Text Solution

    |

  15. The vapour pressure of a dilute solution of a solute is influenced by ...

    Text Solution

    |

  16. In the depression of freezing point experiment, it is found that the:

    Text Solution

    |

  17. Which of the following statements are correct for van't Hoff factor 'i...

    Text Solution

    |

  18. For a dilute solution having molality m of of a given solute in a solv...

    Text Solution

    |

  19. Which facts are true when we use van't Hoff equation PV=CST for osmoti...

    Text Solution

    |

  20. Sodium choride or calcium chloride is used to clear snow from the road...

    Text Solution

    |