Home
Class 12
CHEMISTRY
A liquid possessing which of the followi...

A liquid possessing which of the following characteristics will be most suitable for determining the molecular mass of a compound by cryoscopic measurements?
a.That having low freezing point and small enthalpy of fusion
b.That having high freezing point and small enthalpy of fusion
c.That having hifh freezing point and small enthalpy of vapourization
d.That having large surface tension

Text Solution

Verified by Experts

b. `K_(f)`should be high so as to get a high value of `DeltaT_(f)`
Now `K_(f) prop (T_(f)^(2))/(Delta_(vap)H)`
Promotional Banner

Similar Questions

Explore conceptually related problems

Which of the following 0.1M aqueous solutions will have the lowest freezing point?

Which of the following solutions have lowest freezing point ?

Which of the following equimolar solution is expected to have lowest freezing point ?

Which of the following solutions (1 molal) will have the maximum freezing point, assuming equal ionization in each case?

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?

A solution containing 0.1 mol of naphthalene and 0.9 mol of benzene is cooled out until some benzene freezes out. The solution is then decanted off from the solid and warmed upto 353 K where its vapour pressure was found to be 670 mm . The freezing point and boiling point of benzene are 278.5 K and 353 K respectively, and its enthalpy of fusion is 10.67 KJ "mol"^(-1) . Calculate the temperature to which the solution was cooled originally and the amount of benzene that must have frozen out. Assume ideal behaviour.

Give reason : (i) Most of the transition metals have high melting point and boiling point (ii) 2^(nd) ionization enthalpy of Cu is exceptionally high. (iii) atomic size of 4d- and 5d-series elements are almost the same.

A compound 'X' with molecular formula C_2H_4 burns with a sooty flame. It decolourises bromine water. Will it have high melting point or low melting point?