LGT CLASSES (b) Liquids are highly compressible

(c) Solubility of solid in liquid is directly proportional to partial pressure

CHEMISTRY BY SAPNA MAAM (d) Solids and liquids are highly incompressible
CHAPTER 1: SOLUTIONS 8. To increase the solubility of CO 2 gas in soft drinks, the bottle is sealed
1. Considering the formation, breaking and strength of hydrogen bond, under [CBSE 2021] [Level-I]
predict which of the following mixtures will show a positive deviation (a) Low pressure (b) High temperature (c) Constant pressure (d) High
from Raoult's law? pressure
(a) Methanol and acetone (b) Chloroform and acetone (c) Nitric acid 9. An unknown gas 'X' is dissolved in water at 2.5 bar pressure and has
and water (d) Phenol and aniline mole fraction 0.04 in solution. The mole fraction of 'X' gas when the
pressure of gas is doubled at the same temperature is [CBSE 2021]
2. Which of the following is maximum boiling azeotropic? (a) 0.08 (b) 0.04 (c) 0.02 (d) 0.92
(a) CH3COOH + C5H5N (pyridine) 10. Isotonic solutions have the same [CBSE 2024] [Level-Il]
(b) H2O+ ethanol (a) density (b) refractive index (c) osmotic pressure (d) volume
(c) cyclohexane + ethanol 11. Which of the following law is related to the partial pressure of gas in
(d) H2O + methanol [NCERT Exemplar] [Level-I] liquid? [CBSE 2021] [Level-I|
3. On the basis of information given below mark the correct option. (a) Raoult's law (b) Henry's law (c) Dalton's law (d) Boyle's law
[NCERT Exemplar] Information: 12. For determination of molar mass of polymers and proteins, which
(A) In bromoethane and chloroethane mixture intermolecular colligative property is used? (CBSE 2023, 21] [Level-I]
interactions of A-A and B-B type are nearly same as A-B type (a) Relative lowering in vapour pressure (b) Elevation in boiling point
interactions. (B) In ethanol and acetone mixture A-A or B-B type (c) Osmotic pressure (d) Depression in freezing point
intermolecular interactions are stronger than A-B type interactions. (C) 13. A 5% (by mass) solution of glucose (molar mass = 180 g mol) is isotonic with
In chloroform and acetone mixture A-A or B-B type intermolecular 1% solution (by mass) of a substance 'X'. The molar mass of 'X' is [CBSE 2021]
interactions are weaker than A-B type interactions. [Level-I]
(a) Solution (B) and (C) will follow Raoult's law. (a) 36 g mol-1 (b) 18 g mol-1 (c) 72 g mol-1 (d) 900 g mol-1
(b) Solution (A) will follow Raoult's law. 14.Which of the following liquid pairs shows a positive deviation from Raoult's
(c) Solution (B) will show negative deviation from Raoult's law. law?
(d) Solution (C) will show positive deviation from Raoult's law. (a) Water - Nitric acid (b) Benzene - Methanol
4. Which of the following will have lowest vapour pressure? (Boiling (c) Water - Hydrochloric acid (d) Acetone – Chloroform
points are given in brackets) INCERT Exemplar] [Level-I| 15.1 mole of liquid 'A' and 2 moles of liquid 'B' make a solution with total
(a) H2O (373 K) (b) CHCl (334 K) (c) Aniline (457 K) (d) Benzene (353 K) pressure 40 torr. The vapour pressure of pure 'A' and pure 'B' are 45 torr and 30
5. An ideal solution containing xa = 0.2 has vapour pressure = 350 torr. torr respectively. The above solution [CBSE 2023] [Level-II] (a) is an ideal
Another ideal solution containing X = 0.2 has V.P = 410 torr. P° is equal solution (b) shows positive deviation (c) shows negative deviation (d) is
to [Level-II] (a) 300 torr (b) 430 torr (c)314 torr (d) 350 torr maximum boiling azeotrope
6. Solubility of gas in liquid decreases with increase in 16.Which one of the following will have the highest van't Hoff factor?
(a) pressure (b) volume (c) temperature (d) number of solute particles (a) K2SO 4 (b) MgSO 4 (c) KCl (d) NaCl
7. Pressure does not have any significant effect on solubility of solids in 17.A compound undergoes tetramerisation in a given organic solvent. The van't
liquids because: [CBSE 2021] [Level-I] Hoff factor (i) is [CBSE 2023] [Level-I]
(a) Solids are highly compressible (a) 4.0 (b) 0.25 (c) 0.125 (d) 2.0
18.Volume of 0.02 M HBr in mL needed to completely neutralise 10 mL of 0.01 5. Concentrated nitric acid used in laboratory work is 68% nitric acid by mass in
M Ba(OH)2 in aqueous solution. What should be the molarity of such a sample of the acid if
(a) 20 mL (b) 10 mL (c) 30 mL (d) 40 mL the density of solution is 1.504g/ml?
6. A solution is obtained by mixing 300 g of 25% solution and 400 g of 40%
19. For an electrolyte undergo dissociation in aqueous (a) is always less than
solution by mass. Calculate the mass percentage of the resulting solution.
one (CBSE 2023) [Level-I| 7. H2S, a toxic gas with rotten egg like smell, is used for the qualitative analysis.
(a) is always less than one (b) is always greater than one (c) has zero value (d) If the solubility of H2S in water at STP is 0.195 m, calculate Henry's law
has negative value constant.
20. Which has the highest freezing point? 8. Why do gases always tend to be less soluble in liquids as the temperature is
(a) 1 M glucose (b) 1 MNaCl (c) 1 M CaCl2 (d) 1 M AlF3 raised?
9. Calculate the solubility of CO 2 in water at 298 K under 760 mm Hg.
21. The molarity of the solution containing 7.1 g of Na 2SO 4 (M = 142 g/mol) in
[KH for CO 2 in water at 298 K is 1.25 × 10 6 mm Hg]
100 ml of aqueous solution is
10. (i) Gas A is more soluble in water than gas 'B' at the same temperature.
(a) 2 M (b) 0.5 M (c) 1M (d) 0.05M Which one of the two gases will have higher value of KH?
23. Conc. H2SO 4 is 98 % H2SO 4 by mass has d = 1.84 g cm-3. Volume of acid (ii) What is effect of temperature on solubility of gas in liquid?
required to make one litre of 0.1 M H2SO 4 is [Level-I] 11. The vapour pressure of pure liquid X and pure liquid Y at 25°C are 120 mm
(a) 5.55 mL (b) 10 mL (c) 20 mL (d) 30 mL Hg and 160 mm Hg respectively. If equal moles of X and Y are mixed to form an
ideal solution, calculate the vapour pressure of the solution.
24. What is mole fraction of solute in 1.00 m aqueous solution? [Level-I] (a)
12. Define azeotropes. What type of azeotrope is formed by negative deviation
0.0354 (b) 0.0177 (c) 0.177 (d) 1.770
from Raoult's law? Give an example. [CBSE 2023]
25. The molarity of a solution containing 5g of NaOH in 450 mL of solution is 13. Write two difference between ideal solutions and non-ideal solutions.
[Level-I] [CBSE 2023]
(a) 0.278 × 10-3 M (b) 0.278 M (c) 2.78 × 10 -3 M (d) 2.78 M 14. State Raoult's law for a solution containing volatile components. What is
26. Amalgam of mercury with sodium is: [Level-ll (a) Liquid in liquid (b) Liquid in the similarity between Raoult's law and Henry's law? [CBSE 2020]
solid (c) Solid in solid (d) None of these 15.. Why a mixture of carbon disulphide and acetone shows positive deviation
from Raoult's law? What type of azeotrope is formed by this mixture?
27. Camphor in N2 gas is an example of:
[CBSE 2018]
(a) Gas in gas (b) Solid in gas (c) Gas in solid (d) Liquid in gas 16. Calculate the osmotic pressure in pascals exerted by a solution prepared by
28. Which of the following is an example of solid in liquid? (a) Glucose in water dissolving 1.0 g of polymer of molar mass 185,000 in 450 mL of water at 37 °C.
(b) Sulphur in CSz (c) Urea in water (d) All of these [R = 8.314 Pa]
Very short answer type question 17. Calculate the mass of a non-volatile solute (molar mass 40 g mol-1) which
1. What role does he molecular interaction play in solution of alcohol and should be dissolved in 114 g octane to reduce its vapour pressure to 80%.
water? 18. Derive expression for Raoult's law when the solute is non-volatile.
2. Define the following terms: 19. How is vapour pressure of solvent affected when a non-volatile solute is
(i) Mole fraction (ii) Molality dissolved in it?
(iii) Molarity 20. For a 5% solution of urea (Molar mass = 60 g/mol), calculate the osmotic
(iv) Mass percentage. pressure at 300 K.
[R = 0.0821 L atm K-1 mol-1] (CBSE 2020)
3. Calculate the mass percentage of benzene (C 6H6) and carbon tetrachloride
21. Determine the amount (moles) of CaCl2 (i = 2.47) dissolved in 2.5 litre of
(CCl4) if 22 g of benzene is dissolved in 122 g of carbon tetrachloride.
water such that its osmotic pressure is 0.75 atm at 27 °C. [NCERT] (HOTS)
4. Calculate the mass of urea (NH2CONH2) required in making 2.5 kg of 0.25
22. Determine the osmotic pressure of a solution prepared by dissolving 25 mg
molal aqueous solution.
of K2SO 4 in 2 litre of water at 25°C, assuming that it is completely dissociated.
23. An aqueous solution of sodium chloride freezes below 273 K. Explain the
lowering in freezing points of water with the help of a suitable diagram.
24. A 1.00 molal aqueous solution of trichloroacetic acid (CCI3COOH) is heated (ii) Determine the osmotic pressure of solution prepared by dissolving
to its boiling point. The solution has the boiling point of 100.18 °C. 2.32 x 10-2 g of K2SO 4 in 2 L solution at 25° C assuming K2SO 4 is
Determine the van't Hoff factor for trichloroacetic acid. [Kb for water = 0.512 K completely dissociated. [ R = 0.082 Latm K-1 mol -1, Molar mass of
kg mol-1]
K2SO 4 = 174 g mol-1]
SHORT ANSWER TYPE QUESTION
1.A solution 0.1 M of Na2SO 4 is dissolved to the extent of 95%. What would be (iii) When 25.6 g sulphur was dissolved in 1000g of benzene, the
its osmotic pressure at 27°C? (R=0.0821 L atm K-1 mol-1) freezing point lowered by 0.512 K. Calculate the formula of sulphur (S x )
2. 3.9g of Benzoic acid dissolved in 49g of benzene shows depression in [Kf for benzene = 5.12 K kg mol-1, Atomic mass of sulphur = 32 g mol-1
frezzing point 1.62 K. Calculate the van’t Hoff factor and predict the nature of [CBSE 2023]
solute (associated or dissocated), Given molar mass of benzoic acid= 122 g
2. (a) A 4% solution (w/w) of sucrose (M = 342 g mol-1) in water has a
mol-1 Kf for bezene = 4.9 K kg mol-1) (CBSE 2023)
3.Based on solute-solvent interactions, arrange the following in order of freezing point of 271.15 K. Calculate the freezing point of 5% glucose
increasing solubility in n-octane and explain. Cyclohexane, KCl, CH3OH, (M = 180 g mol-1) in water. (Given: Freezing point of pure water = 273.15
CH3CN. K) [Delhi 2019]
4.Amongst the following compounds, identify which are insoluble, partially (b) A solution prepared from 1.25 g of oil of wintergreen (methyl
soluble and highly soluble in water? (i) phenol, (ii) toluene, (iti) formic acid, (iv) salicylate) in 90.0 g of benzene has a boiling point of 80.31 °C.
ethylene glycol, (v) chloroform, (vi) pentanol.
Determine the molar mass of this compound. (Boiling point of pure
5. Calculate the molarity of each of the following solutions: (a) 30 g of Co(NO 3)2.
6H2O in 4.3 L of solution. [Molar Mass of Co(NO 3)2.6H2O = 291 g/ mol] (b) 30 mL benzene = 80.10 °C and Kb for benzene = 2.53 °C kg mol-1).
of 0.5 M H2SO 4 diluted to 500 mL. [NCERT Intext] 3. Suggest the most important type of intermolecular attractive
6. Calculate (a) molality, (b) molarity and (c) mole fraction of KI if the density of interaction in the following pairs:
20% (mass/mass) aqueous KI is 1.202 g mL [NCERT Intext] [Molar Mass of KI = (i) n-hexane and n-octane, (ii) I2 and CCI4 (iii) NaCIO 4 and water, (iv)
166 g/mol] methanol and acetone, (v) acetonitrile (CH3CN) and acetone (C3H6O).
7. 6.90 M solution of KOH in water contains 30% by mass of KOH. Calculate
ASSERTION AND REASON QUESTIONS
density and molality of KOH solution. [K = 39, 0 = 16, H = 1]
In the following questions (Q. No. 1 - 10), a statement of assertion followed by
8. ⁠Heptane and octane form an ideal solution. At 373 K, the vapour pressures of statement of a reason is given. Choose the correct answer out of the following
the two liquid components are 105.2 kPa and 46.8 kPa respectively. What will
choices.
be the vapour pressure of a mixture of 26.0 g of heptane (M = 100g/mol) and
(a) Both A and R are true and R is the correct explanation of A.
35.0 g of octane (M = 114g/mol)? (b) Both A and R are true but R is not the correct explanation of A.
9. State Henry's law and mention some important applications. [CBSE 2023;
(c) A is true but R is false.
2020(C)]
(d) A is false but R is true.
10. How does mole fraction of HCl gas in its solution in cyclohexane varies with
1. Assertion (A): When methyl alcohol is added to water, boiling point of water
partial pressure of HCl(g)? Show with the help of graph? How can we calculate increases.
KH with the help of graph? Name two factors which affect the value of K H?
Reason (R): When a non-volatile solute is added to a volatile solvent elevation in
11. State Raoult's law for a solution containing nonvolatile solute. What type of
boiling point is observed.
deviation from Raoult's law is shown by a solution of chloroform and acetone
2. Assertion (A): When a solution is separated from the pure solvent by a
and why?
semipermeable membrane, the solvent molecules pass through it from pure
12. ⁠The vapour pressure of water is 12.3 kPa at 300 K. Calculate vapour solvent side to the solution side.
pressure of 1 molal solution of a non-volatile solute in it. Reason (R): Diffusion of solvent occurs from a region of high concentration
LONG ANSWER TYPE QUESTIONS solution to a region of low concentration solution.
1. (i) Why is value of van't Hoff factor for ethanoic acid in benzene closed 3. Assertion (A): Soft drink bottles are sealed under high pressure.
to 0.5? Reason (R): The dissolution of gas in liquid is an endothermic process.
(KVS 2022)
4. Assertion (A): The aquatic species feel more comfortable in winter than (c) The vapour pressure of a solution of glucose in water is 750 mm Hg at 100°C.
summer. Calculate the mole fraction of solute. (Vapour pressure of water at 373 K = 760
Reason (R): Solubility of gases in liquid increases with increase in temperature. mm Hg)
5. Assertion (A): Azeotropic mixtures are formed only by non-ideal solution. Or
Reason (R): Boiling point of azeotropes is either higher or lower than both the (c) The boiling point of solution increases when 1 mol of NaCl is added to 1 litre
components. of water while addition of 1 mol of methanol to one litre of water decreases its
(KVS 2022) boiling point. Explain the above observations.
6. Assertion (A): An aqueous solution of NaCl freezes below 273 K. 2. Read the following passage and answer the questions that follow:
Reason (R): Vapour pressure of solution is less than that of pure solvent. There are many phenomena which we observe in nature or at home. For
[CBSE 2023; KVS 2022] example, raw mangoes shrink when pickled in brine, wilted flowers revive in
7. Assertion (A): When glucose is added to water, an elevation in boiling point is fresh water, etc. The substances are bound by membranes. Small molecules
observed. like water can pass through these membranes. This process of flow of solvents
Reason (R): The lowering of vapour pressure causes elevation in boiling point. is called osmosis. The pressure that just stops the flow of solvents is called
[CBSE 2023] osmotic pressure of solution. Osmotic pressure is directly proportional to
8. Assertion (A): 0.1 M solution of KCl has greater osmotic pressure than 0.1 M molarity of the solution at a given temperature. [CBSE 2020(C)]
solution of glucose at same temperature. (a) Out of 1 M urea and 1 M NaCl, which one has higher osmotic pressure of the
Reason (R): In solution, KCl dissociates to produce more number of particles. solution?
[CBSE 2020] Or
CASE BASED STUDY Name one natural and one synthetic membrane that can be used in osmosis.
Read the following passage and answer the questions that follow: (b) A doctor advised a person suffering from high blood pressure to take less
Raoult's law for volatile liquids states that the partial vapour pressure of each quantity of salt. Why?
component in the solution is directly proportional to its mole fraction, whereas (c) How can we convert sea water into potable water?
for a non-volatile solute, it states that the vapour pressure of a solution of a (d) The Red Blood Corpuscles (RBC) in animal cells are isotonic with 0.9% NaCl
non-volatile solute is equal to the vapour pressure of the pure solvent at that solution. What will happen when RBCs are placed in 1% NaCl solution ?
temperature multiplied by its mole fraction. Two liquids A and B are mixed with
each other to form a solution. Once the components in the solution have
reached equilibrium, the total vapour pressure of the solution can be
determined by combining Raoult's law with Dalton's law of partial pressures. If
a non-volatile solute B is dissolved into a solvent A to form a solution, the
vapour pressure of the solution will be lower than that of the pure solvent.
The solutions which obey Raoult's law over the entire range of concentration
are ideal solutions, whereas the solutios for which vapour pressure is either
higher or lower than that predicted by Raoult's law are called non-ideal
solutions. Non-ideal solutions are identified by determining the strength of the
intermolecular forces between the different molecules in that particular
solution.
They can either show positive or negative deviation from Raoult's law depending
on whether the A - B interactions in solution are stronger or weaker than A - A
and B - B interactions. [CBSE 2023(C)]
(a) 20 mL of a liquid A was mixed with 20 ml of liquid B. The volume of resulting
solution was found to be less than 40 mL. What do you conclude from the
above data?
(b) Which of the following show positive deviation from Raoult's law?
Carbon disulphide and Acetone; Phenol and Aniline; Ethanol and Acetone.