Q. 28

(a) Differentiate

Answer :

(a) Molarity: It is the number of moles of solute dissolved in 1 litre of the solution. It is temperature dependent.

Molality: It is the number of moles of solute dissolved in 1 kg of the solvent. It is temperature independent.

Molality is independent of temperature, whereas molarity is a function of temperature because volume depends on temperature and mass does not.

(b) Given: w= 10.50 g

W= 200 g

= 184 g

Kƒ = 1.86 K kgmol-1

MgBr2 dissociates as per the given equation:

MgBr2 Mg2+ + 2Br-

So, total no. of moles after dissociation = 1+2 = 3

Thus, i = = 3

Using the formula

Tƒ = i×Kƒ×m

T0f–Tf =

0-Tf =

-Tf = = 1.592

Tf = -1.592

Or Tf = -271.56 K


(a) Osmosis: Osmosis is the phenomenon of flow of solvent through a semi-permeable membrane from the region of higher concentration to the region of lower concentration.

Osmotic Pressure: The osmotic pressure of a solution is the excess pressure that must be applied to the solution to prevent the passage of solvent molecule through a semi-permeable membrane into the solution.

Yes, osmotic pressure is a colligative property as it depends only on the amount of solute present in the solution.

(b) Given: w= 15 g

W= 250g

= 58.44 g

Kb = 0.512 K kgmol-1

NaCldissociates as per the given equation:

NaCl Na+ + Cl-

So, total no. of moles after dissociation = 1+1 = 2

Thus, i = = 2

Using the formula

Tb = i×Kb×m

Tb – T0b=

Tb –373=

Tb= = 1.05 + 373

Tb = 374.05 K

or Tb = 101.05

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses

A statement of asChemistry - Exemplar

Match the laws giChemistry - Exemplar