Topic 1 : concentration terms
Assignment 1
1. When and why is molality preferred over molarity in handling solutions in chemistry?
2. What is the effect of temperature on molarity of a solution?
3. Which solution has higher concentration , 1 molar or molar or solution of the same solute? Give reason.
4. V1 cc of solution having molarity M1 Is diluted to have molarity M2. Derive expression (in terms of M1, M2
and V1 ) for the volume of water required to be added.
5. How is the molaity of a solution different from its molarity ?
6. Why the solubility of ‘Glauber’s (Na2SO4) first increases up to 32-40 0C and then decreases?
Assignment 2
1. How is it that alcohol (ethoxyethane)and water are miscible in all proportions?
2. Give an example of a solution containing a liquid solute in a solid solvent.
3. Give one example each of soild in gas and liquid in gas solutions.
4. What do you mean by saying that the molaity of a solution is 0.1?
5. What is the relation between normality and molarity of a given solution of H2SO4
6. What is the sum of mole fractions of all the components in a three component system?
7. Why does the molality of a solution remain unchanged with temperature?
8. Calculate the molarity of H2O.
9. What is the effect of temperature on the solubility of sodium sulphate decahydrate?
10. Define transition temperature in solubility of a solid in a liquid.
Assignment 3
1. To what type of solution an alloy belongs ? Give one example of a solution of liquid in solid.
2. Explain the terms ‘Mass fraction’ and ‘Mole fraction’ ?
3. Which out of molality, molarity and mole fraction of a solution will remain unchanged on raising the
temperature and why ?
4. Differentiate between molality and molarity of a solution. What is the effect of change ion temperature of a
solution on its molality and molarity ?
5. Discuss the effect of temperature on the solubility of solids in liquids.
Topic 2 : Solubility of Solid in liquid (Relative lowering in vapour pressure) Solubility of liquid
in liquid (Raoult’s law), Solubility of gas in liquid(Henry’s law)
Assignment 1
1. State Henry’s law correlating the pressure of a gas and its solubility in a solvent and mention two applications
for the law. What helps in existence of aquatic life ?
Or
State Henry’s law ad mention its two important applications.
2. How can you justify the observation that the vapour pressure of solution o of a non-volatile solute in a given
solvent is less than that of the pure solvent ? Also state the law concerning this observation.
3. State Raoult’s law. Derive its mathematical expression for a solution of a non-volatile solute in a volatile
solvent.
4. Vapour pressure of a solution is different from that of pure solvent
(i) Name the law which helps us to determine partial vapour pressure of a volatile component is solution.
(ii) State the above law.
5. Define vapour pressure of a liquid. What happens to the vapour pressure when (a) a volatile solute dissolves in
the liquid and (b) the dissolved solute is non-volatile.
6. Show that the relative lowering of vapour pressure for a solution is equal to the mole fraction of the solute
when solvent alone is volatile.
Or
What do you understand by Relative lowering of vapour pressure ? How is it used to determine molecular
mass of the solute ?
7. Draw a suitable labeled diagram to express the relationship for ideal solution of A and B between vapour
pressure and mole fractions of components at constant temperature.
8. Non-ideal solutions exhibit either positive or negative deviations from Raoult’s law. What are these deviations
and why are they caused ? Explain with one example of each type.
