BAL VIDYA INSTITUTE M.no.9810913697
Contact: I-Block 4/218 Sangam Vihar N.D.110080 8700255096
SOLUTIONS
1) What is ‘reverse osmosis’?
Ans. If the pressure applied on the solution is greater than the osmotic pressure then the solvent molecules start to
move from solution into solvent through semi permeable membrane. This process is called reverse osmosis.
2) How is the molality of a solution different from its molarity?
Ans. Molality of a solution is the number of moles of the solute present in 1 kg of the solvent and does not change with
temperature. Molarity of a solution is the number of moles of the solute present in 1 litre of the solution and
changes with temperature.
3) Give an example of solution containing a solid solute in a solid solvent.
Ans. Alloys like copper in gold.
4) How does the molarity of a solution change with temperature?
Ans. Molarity decreases with increase in temperature as volume of solution increases with increase in temperature.
5) When and why is molality preferred over molarity in handling solutions in chemistry?
Ans. Molality is preferred when studies are made on processes which depend on temperature. This is because molality
depends on masses of solvent which do not change with temperature.
6) Which aqueous solution has higher concentration 1 molar or 1 molal solution of the same solute? Give reasons.
Ans. 1M solution means 1 mole of the solute in 1000cc of the solution whereas 1 m solution means 1 mole of the
solute in 1000g of water (= 1000cc of water). Total volume of 1 m solution > 1000 cc due to presence of extra 1 mole
of solute. Hence, number of moles/cc in 1 m solution will be less than that in 1 M solution. In other words, 1 M is more
concentrated than 1 m.
7) Why is glycol and water mixture used in car radiators in cold countries?
Ans. Ethylene glycol lowers the freezing point of water. Due to this, coolant in radiators will not freeze. Otherwise,
radiator will burst due to freezing of coolant (water).
8) Two liquids A and B on mixing produce a warm solution. Which type of deviation from Raoult’s law does it show?
Ans. Warming uo of the solution means that the process of mixing is exothermic, i.e., Δ𝐻𝑚𝑖𝑥𝑖𝑛𝑔 = − ve. This implies
that the solution shows a negative deviation from Raoult’s law.
9) What do you understand by ‘ colligative properties’?
Ans. Colligative properties are those properties which depend upon the number of moles of solute particle but not on
the nature of solute particles.
Contact: I-Block 4/218 Sangam Vihar N.D.110080 8700255096
SOLUTIONS
1) What is ‘reverse osmosis’?
Ans. If the pressure applied on the solution is greater than the osmotic pressure then the solvent molecules start to
move from solution into solvent through semi permeable membrane. This process is called reverse osmosis.
2) How is the molality of a solution different from its molarity?
Ans. Molality of a solution is the number of moles of the solute present in 1 kg of the solvent and does not change with
temperature. Molarity of a solution is the number of moles of the solute present in 1 litre of the solution and
changes with temperature.
3) Give an example of solution containing a solid solute in a solid solvent.
Ans. Alloys like copper in gold.
4) How does the molarity of a solution change with temperature?
Ans. Molarity decreases with increase in temperature as volume of solution increases with increase in temperature.
5) When and why is molality preferred over molarity in handling solutions in chemistry?
Ans. Molality is preferred when studies are made on processes which depend on temperature. This is because molality
depends on masses of solvent which do not change with temperature.
6) Which aqueous solution has higher concentration 1 molar or 1 molal solution of the same solute? Give reasons.
Ans. 1M solution means 1 mole of the solute in 1000cc of the solution whereas 1 m solution means 1 mole of the
solute in 1000g of water (= 1000cc of water). Total volume of 1 m solution > 1000 cc due to presence of extra 1 mole
of solute. Hence, number of moles/cc in 1 m solution will be less than that in 1 M solution. In other words, 1 M is more
concentrated than 1 m.
7) Why is glycol and water mixture used in car radiators in cold countries?
Ans. Ethylene glycol lowers the freezing point of water. Due to this, coolant in radiators will not freeze. Otherwise,
radiator will burst due to freezing of coolant (water).
8) Two liquids A and B on mixing produce a warm solution. Which type of deviation from Raoult’s law does it show?
Ans. Warming uo of the solution means that the process of mixing is exothermic, i.e., Δ𝐻𝑚𝑖𝑥𝑖𝑛𝑔 = − ve. This implies
that the solution shows a negative deviation from Raoult’s law.
9) What do you understand by ‘ colligative properties’?
Ans. Colligative properties are those properties which depend upon the number of moles of solute particle but not on
the nature of solute particles.
