2025[CHEMISTRY SIMPLY THE BEST……..ENJOY CHEMISTRY ]
Unit: 2:-SOLUTIONS
TOPIC: TYPE OF SOLUTION & CONCENTRATION OF SOLUTIONS
Type of Solution Solute Solvent Common Examples
Gaseous Solutions Gas Gas Mixture of oxygen and nitrogen gases
Liquid Gas Chloroform mixed with nitrogen gas
Solid Gas Camphor in nitrogen gas
Liquid Solutions Gas Liquid Oxygen dissolved in water
Liquid Liquid Ethanol dissolved in water
Solid Liquid Glucose dissolved in water
Solid Solutions Gas Solid Solution of hydrogen in palladium
Liquid Solid Amalgam of mercury with sodium
Solid Solid Copper dissolved in gold
Mass of solute
1. Mass per cent (w/w)= 100 ,
Mass of solution
If a solution is described by 10% glucose in water by mass, it means that 10 g of glucose is dissolved in
90 g ofwater resulting in a 100 g solution
Volume of the component
2. Volume percentage (v/v): 100 ,
Total volume of solution
For example, 10% ethanol solution in water means that 10 mL of ethanol is dissolved in water such
that the total volume of the solution is 100 ml.
3. Mass by volume percentage (w/v): It is the mass of solute dissolved in 100 mL of the solution.
4. Parts per million (ppm). It is defined as the amount of substance in grams in 10 6 of solution. e.g.,
10 ppm of SO2 means 10 cm3 of SO2 present in 106 cm3 of air.
Mass of solute 6
ppm= 10
Mass of solution
5. Mole-fraction (x). It is ratio of number of moles of a particular component to the total number of
moles of all the components.
No. of moles of solute
Mole-fraction of solute(B) =
No. of moles of solute No. of moles of solvent
WB
nB MB
xB
nA nB WA WB
MA WB
No. of moles of solvent
Mole-fraction of solvent (A)=
No. of moles of solute No. of moles of solvent
WA
nA M A
Thus xB + xA = 1
xA
nA nB WA WB
M A WB
6. Molarity (M). It is expressed as the number of moles of solute per litre of solution..
No. of moles of solute Wsolute 1000
Molarity (M)=
Litres of solution Msolute Volume of solution (ml).
Wsolute 1000 x density of Solution
M =
Msolute Mass of solution .
7. Molality (m). It is defined as number of moles of solute per 1000 g or 1 kg of solvent.
No. of moles of solute Wsolute 1000
(m) =
Kg. of solvent Msolute WSolvent in grams.
MAHENDRA KALRA 1
, 2025[CHEMISTRY SIMPLY THE BEST……..ENJOY CHEMISTRY ]
QUESTION BASED ON MOLALITY, MOLARITY, MASS PERCENTAGE, VOLUME PERCENTAGE,
PARTSPERMILLION MOLE FRACTION
1. Define: Molality, Molarity, Mass percentage, Volume percentage, Partspermillion (ppm), Mole
fraction. Write their formulas also.
2. Which out of the Molality & Molarity is better way to express the concentration of solution and why?
3. How does a change in temperature influence values of molarity and molality.
4. Concentration terms such as mass percentage, ppm, mole fraction and molality are independent of
temperature, however molarity is a function of temperature.Explain.
5. Under what conditions molarity and molality of a solution nearly the same.
6. A solution is heated from 25oC to 50oC.Will its molarity be same less or more. Comment.
7. What is the sum of the mole fractions of all the components in a three component system?
8. Calculate the molarity of a solution containing 5 g of NaOH in 450ml solution.
9. Calculate molality of 2.5g of ethanoic acid (CH3COOH) in 75g of benzene.
10. Calculate the molarity of each of the following solutions :( a) 30g of Co(NO3)2.6H2O in 4.3L of solution
(b) 30ml of 0.5H2SO4 diluted to 500ml.
11. Calculate Molality, Molarity & Mole fraction of KI if the density of 20 %( mass/mass) aqueous KI is
1.202g/ml.
12. Concentrated nitric acid used in the laboratory work is 68% nitric acid by mass in aqueous solution.
What should be the molarity of such a sample of the acid if the density of the solution is 1.504 g/ml?
13. An antifreeze solution is prepared from 222.6g of ethylene glycol. C2H4 (OH) 2 and 200g of water.
Calculate molality of solution. If the density of the solution is 1.072 g/ml then what shall be the
molarity of the solution?
14. A solution of glucose in water is labelled as 10% w/w. What should be the molality and mole fraction
of each component in the solution? If the density of solution is 1.2g/ml, then what shall be the
molarity of the solution?
15. If the density of some lake water is 1.25 g/ml and contains 92g of Na+ ions per Kg of water, calculate
the molality and molarity of Na+ ions in the lake.
16. Calculate the amount of benzoic acid required for preparing 250 ml of 0.15M solution in methanol.
17. Calculate the mass percentage of benzene (C6H6) and carbon tetrachloride (CCl4)if 22g of benzene is
dissolved in 122g of carbon tetrachloride (CCl4).
18. Calculate the mole fraction of ethylene glycol. C2H4 (OH) 2 in a solution containing 20% of ethylene
glycol. C2H4 (OH) 2 by mass.
19. Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride
(CCl4).
20. Calculate the mass of urea (NH2CONH2) required in making 2.5 Kg of 0.25 molal of aqueous solution.
21. Calculate the mass percentage of aspirin (C9H8O4) in acetonitrile (CH3CN)when 6.5g of (C9H8O4) in
dissolved in 450g of (CH3CN).
22. A sample of drinking water was found to be contaminated with chloroform (CHCl 3) supposed to be
carcinogen. The level of contamination was 15ppm (By mass). (i) Express this in percent by mass.
(ii)determine the molality of chloroform in the water sample.
23. Nalorphene (C19H21NO3), similar to morphine is used to combat withdrawal symptoms in narcotic
users .Dose of Nalorphene, generally is 1.5 mg.Calculate the mass of 1.5 X 10 -3 molal aqueous solution
for the dose.
24. If the solubility product of CuS is 6 X 10-16, calculate the maximum molarity of CuS in aqueous solution.
25. Calculate the percentage composition in terms of mass of a solution obtained by mixing 300g of a 25%
and 400g of 40% solution by mass.
TOPIC : SOLUBILITY OF A GAS IN A LIQUID, HENRY LAW & APPLICATIONS
1. Henry’s law.(Statements)
The law states that at a constant temperature, the solubility of a gas in a liquid is directly
proportional to the pressure of the gas.
MAHENDRA KALRA 2
Unit: 2:-SOLUTIONS
TOPIC: TYPE OF SOLUTION & CONCENTRATION OF SOLUTIONS
Type of Solution Solute Solvent Common Examples
Gaseous Solutions Gas Gas Mixture of oxygen and nitrogen gases
Liquid Gas Chloroform mixed with nitrogen gas
Solid Gas Camphor in nitrogen gas
Liquid Solutions Gas Liquid Oxygen dissolved in water
Liquid Liquid Ethanol dissolved in water
Solid Liquid Glucose dissolved in water
Solid Solutions Gas Solid Solution of hydrogen in palladium
Liquid Solid Amalgam of mercury with sodium
Solid Solid Copper dissolved in gold
Mass of solute
1. Mass per cent (w/w)= 100 ,
Mass of solution
If a solution is described by 10% glucose in water by mass, it means that 10 g of glucose is dissolved in
90 g ofwater resulting in a 100 g solution
Volume of the component
2. Volume percentage (v/v): 100 ,
Total volume of solution
For example, 10% ethanol solution in water means that 10 mL of ethanol is dissolved in water such
that the total volume of the solution is 100 ml.
3. Mass by volume percentage (w/v): It is the mass of solute dissolved in 100 mL of the solution.
4. Parts per million (ppm). It is defined as the amount of substance in grams in 10 6 of solution. e.g.,
10 ppm of SO2 means 10 cm3 of SO2 present in 106 cm3 of air.
Mass of solute 6
ppm= 10
Mass of solution
5. Mole-fraction (x). It is ratio of number of moles of a particular component to the total number of
moles of all the components.
No. of moles of solute
Mole-fraction of solute(B) =
No. of moles of solute No. of moles of solvent
WB
nB MB
xB
nA nB WA WB
MA WB
No. of moles of solvent
Mole-fraction of solvent (A)=
No. of moles of solute No. of moles of solvent
WA
nA M A
Thus xB + xA = 1
xA
nA nB WA WB
M A WB
6. Molarity (M). It is expressed as the number of moles of solute per litre of solution..
No. of moles of solute Wsolute 1000
Molarity (M)=
Litres of solution Msolute Volume of solution (ml).
Wsolute 1000 x density of Solution
M =
Msolute Mass of solution .
7. Molality (m). It is defined as number of moles of solute per 1000 g or 1 kg of solvent.
No. of moles of solute Wsolute 1000
(m) =
Kg. of solvent Msolute WSolvent in grams.
MAHENDRA KALRA 1
, 2025[CHEMISTRY SIMPLY THE BEST……..ENJOY CHEMISTRY ]
QUESTION BASED ON MOLALITY, MOLARITY, MASS PERCENTAGE, VOLUME PERCENTAGE,
PARTSPERMILLION MOLE FRACTION
1. Define: Molality, Molarity, Mass percentage, Volume percentage, Partspermillion (ppm), Mole
fraction. Write their formulas also.
2. Which out of the Molality & Molarity is better way to express the concentration of solution and why?
3. How does a change in temperature influence values of molarity and molality.
4. Concentration terms such as mass percentage, ppm, mole fraction and molality are independent of
temperature, however molarity is a function of temperature.Explain.
5. Under what conditions molarity and molality of a solution nearly the same.
6. A solution is heated from 25oC to 50oC.Will its molarity be same less or more. Comment.
7. What is the sum of the mole fractions of all the components in a three component system?
8. Calculate the molarity of a solution containing 5 g of NaOH in 450ml solution.
9. Calculate molality of 2.5g of ethanoic acid (CH3COOH) in 75g of benzene.
10. Calculate the molarity of each of the following solutions :( a) 30g of Co(NO3)2.6H2O in 4.3L of solution
(b) 30ml of 0.5H2SO4 diluted to 500ml.
11. Calculate Molality, Molarity & Mole fraction of KI if the density of 20 %( mass/mass) aqueous KI is
1.202g/ml.
12. Concentrated nitric acid used in the laboratory work is 68% nitric acid by mass in aqueous solution.
What should be the molarity of such a sample of the acid if the density of the solution is 1.504 g/ml?
13. An antifreeze solution is prepared from 222.6g of ethylene glycol. C2H4 (OH) 2 and 200g of water.
Calculate molality of solution. If the density of the solution is 1.072 g/ml then what shall be the
molarity of the solution?
14. A solution of glucose in water is labelled as 10% w/w. What should be the molality and mole fraction
of each component in the solution? If the density of solution is 1.2g/ml, then what shall be the
molarity of the solution?
15. If the density of some lake water is 1.25 g/ml and contains 92g of Na+ ions per Kg of water, calculate
the molality and molarity of Na+ ions in the lake.
16. Calculate the amount of benzoic acid required for preparing 250 ml of 0.15M solution in methanol.
17. Calculate the mass percentage of benzene (C6H6) and carbon tetrachloride (CCl4)if 22g of benzene is
dissolved in 122g of carbon tetrachloride (CCl4).
18. Calculate the mole fraction of ethylene glycol. C2H4 (OH) 2 in a solution containing 20% of ethylene
glycol. C2H4 (OH) 2 by mass.
19. Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride
(CCl4).
20. Calculate the mass of urea (NH2CONH2) required in making 2.5 Kg of 0.25 molal of aqueous solution.
21. Calculate the mass percentage of aspirin (C9H8O4) in acetonitrile (CH3CN)when 6.5g of (C9H8O4) in
dissolved in 450g of (CH3CN).
22. A sample of drinking water was found to be contaminated with chloroform (CHCl 3) supposed to be
carcinogen. The level of contamination was 15ppm (By mass). (i) Express this in percent by mass.
(ii)determine the molality of chloroform in the water sample.
23. Nalorphene (C19H21NO3), similar to morphine is used to combat withdrawal symptoms in narcotic
users .Dose of Nalorphene, generally is 1.5 mg.Calculate the mass of 1.5 X 10 -3 molal aqueous solution
for the dose.
24. If the solubility product of CuS is 6 X 10-16, calculate the maximum molarity of CuS in aqueous solution.
25. Calculate the percentage composition in terms of mass of a solution obtained by mixing 300g of a 25%
and 400g of 40% solution by mass.
TOPIC : SOLUBILITY OF A GAS IN A LIQUID, HENRY LAW & APPLICATIONS
1. Henry’s law.(Statements)
The law states that at a constant temperature, the solubility of a gas in a liquid is directly
proportional to the pressure of the gas.
MAHENDRA KALRA 2
