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Solutions Chemistry - Solutions

Uttarakhand Board (UBSE) - STD 12 Science - Chemistry (Uttarakhand - English Medium). 389 questions in this chapter.

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Solutions question types

389 questions across 7 question groups — pick any mix to generate a Chemistry paper with step-by-step answer keys.

389
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5
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Sample Questions

Solutions questions

One sample from each question group in this chapter. Select any group above to see the full set with answer keys.

Q 1M.C.Q (1 Marks)1 Mark
The value of Henry’s constant $K_H$ is $.......$
  • A
    Greater for gases with higher solubility.
  • ✓
    Greater for gases with lower solubility.
  • C
    Constant for all gases.
  • D
    Not related to the solubility of gases.

Answer: B.

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Q 4M.C.Q (1 Marks)1 Mark
Which of the following statements is false?
  • ✓
    Two different solutions of sucrose of same molality prepared in different solvents will have the same depression in freezing point.
  • B
    The osmotic pressure of a solution is given by the equation $\pi=\text{CRT}\ ($where $C$ is the molarity of the solution$).$
  • C
    Decreasing order of osmotic pressure for $0.01M$ aqueous solutions of barium chloride, potassium chloride, acetic acid and sucrose is $\mathrm{BaCl}_2 > \mathrm{KCl} > \mathrm{CH}_3 \mathrm{COOH} > $ sucrose.
  • D
    According to Raoult's law, the vapour pressure exerted by a volatile component of a solution is directly proportional to its mole fraction in the solution.

Answer: A.

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Q 5M.C.Q (1 Marks)1 Mark
What is an example of camphor in $N_2$ gas?
  • ✓
    Solid in gas solution
  • B
    Gas in gas solution
  • C
    Solid in liquid solution
  • D
    Liquid in gas solution

Answer: A.

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Q 6Assertion (A) & Reason (B) MCQ1 Mark
In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: Osmotic pressure is a colligative property.
Reason: Osmotic pressure depends only on the number of particles dissolved in solution.
  • ✓
    Assertion and reason both are correct statements and reason is correct explanation for assertion.
  • B
    Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  • C
    Assertion is correct statement but reason is wrong statement.
  • D
    Assertion is wrong statement but reason is correct statement.

Answer: A.

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Q 7Assertion (A) & Reason (B) MCQ1 Mark
In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: Solutions having the same osmotic pressure are called isotonic solutions.
Reason: $Ca^{2+}$ and $K^+$ ions are responsible for maintaining proper osmotic pressure balance in the cells of organism.
  • A
    Assertion and reason both are correct statements and reason is correct explanation for assertion.
  • B
    Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  • ✓
    Assertion is correct statement but reason is wrong statement.
  • D
    Assertion is wrong statement but reason is correct statement.

Answer: C.

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Q 8Assertion (A) & Reason (B) MCQ1 Mark
In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: One molal aqueous solution of urea contains $60g$ of urea in $1 \ kg$ of water.
Reason: Solution containing one mole of solute in $1000g$ solvent is called one molal solution.
  • ✓
    Assertion and reason both are correct statements and reason is correct explanation for assertion.
  • B
    Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  • C
    Assertion is correct statement but reason is wrong statement.
  • D
    Assertion is wrong statement but reason is correct statement.

Answer: A.

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Q 9Assertion (A) & Reason (B) MCQ1 Mark
In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: Molarity of a solution in liquid state changes with temperature.
Reason: The volume of a solution changes with change in temperature.
  • ✓
    Assertion and reason both are correct statements but the reason is the correct explanation for assertion.
  • B
    Assertion and reason both are correct statements but the reason is not a correct explanation for assertion.
  • C
    Assertion is a correct statement but the reason is a wrong statement.
  • D
    Assertion is a wrong statement but the reason is correct

Answer: A.

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Q 10Assertion (A) & Reason (B) MCQ1 Mark
In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: Sodium chloride used to clear snow on the roads.
Reason: Sodium chloride depresses the freezing point of water.
  • ✓
    Assertion and reason both are correct statements and reason is correct explanation for assertion.
  • B
    Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  • C
    Assertion is correct statement but reason is wrong statement.
  • D
    Assertion is wrong statement but reason is correct statement.

Answer: A.

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Q 162 Marks Questions2 Marks
At absolute zero, an exothermic reaction is always spontaneous but at temperatures above absolute zero, we have to consider both enthalpy and entropy before we can predict spontaneity. Why?
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Q 172 Marks Questions2 Marks
  1. Gas (A) is more soluble in water than Gas (B) at the same temperature. Which one of the two gases will have the higher value of $K_H$ (Henry's constant) and why?
  2. In non-ideal solution, what type of deviation shows the formation of maximum boiling azeotropes?
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Q 182 Marks Questions2 Marks
  1. Why are aquatic species more comfortable in cold water than in warm water?
  2. What happens when we place the blood cell in saline water solution (hypertonic solution)? Give reason.
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Q 202 Marks Questions2 Marks
Define the terms, ‘osmosis’ and ‘osmotic pressure’. What is the advantage of using osmotic pressure as compared to other colligative properties for the determination of molar masses of solutes in solutions?
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Q 213 Marks Question3 Marks
  1. Urea forms an ideal solution in water. Determine the vapour pressure of anaqueous solution containing 10% by mass of urea at 40°C. (Vapour pressure of water at 40°C = 55.3 mm of Hg)
  2. Why is freezing point depression of 0.1 M sodium chloride solution nearly twice that of 0.1 M glucose solution?
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Q 223 Marks Question3 Marks
Calculate the boiling point of solution when $4\ g$ of $MgSO_4\ (M = 120\ g\ mol^{-1})$ was dissolved in $100\ g$ of water, assuming $MgSO_4$ undergoes complete ionization.
$(K_b$ for water$=0.52\ K\ kg\ mol^{-1}).$
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Q 233 Marks Question3 Marks
Vapour pressure of water at $20^o\ C$ is $17.5\ mm$ Hg. Calculate the vapour pressure of water at $20^o\ C$ when $15\ g$ of glucose $($Molar mass $=180\ g\ mol^{-1})$ is dissolved in $150\ g$ of water.
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Q 243 Marks Question3 Marks
A solution prepared by dissolving 8.95mg of a gene fragment in 35.0mL. of water has an osmotic pressure of 0.335 torr at 25°C. Assuming that the gene fragment is a non-electrolyte, calculate its molar mass.
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Q 253 Marks Question3 Marks
What mass of $\mathrm{NaCl}\left(\right.$ molar mass $\left.=58.5 \mathrm{~g} \mathrm{~mol}^{-1}\right)$ must be dissolved in $65$ g of water to lower the freezing point by $7.50^{\circ} \mathrm{C}$ ? The freezing point depression constant, $\mathrm{K}_{\mathrm{f}}$, for water is $1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$. Assume van't Hoff factor for $NaCl$ is $1.87.$
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Q 26Case study (4 Marks)4 Marks
Read the passage given below and answer the following questions:
At the freezing point of a solvent, the solid and the liquid are in equilibrium. Therefore, a solution will freeze when its vapour pressure becomes equal to the vapour pressure of the pure solid solvent. It has been observed that when a non-volatile solute is added to a solvent, the freezing point of the solution is always lower than that of the pure solvent. Depression in freezing point can be given as, $\Delta\text{T}_\text{f}=\text{K}_\text{f}\text{m}$ Where, $K_f =$ Molal freezing point depression constant or we can write, $\Delta\text{T}_\text{f}=\frac{\text{K}_\text{f}\times\text{W}_\text{B}\times1000}{\text{W}_A\times\text{M}_\text{B}}$
a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
  1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
  2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  3. Assertion is correct statement but reason is wrong statement.
  4. Assertion is wrong statement but reason is correct statement.
  1. Assertion: $0.1M$ solution of glucose has same depression in the freezing point as $0.1M$ solution of urea.
Reason: $K_f $ for both has same value.
  1. Assertion: Increasing pressure on pure water decreases its freezing point.
Reason: Density of water is maximum at $273K.$
  1. Assertion: Larger the value of cryoscopic constant of the solvent, lesser will be the freezing point of the solution.
Reason: Extent of depression in the freezing point depends on the nature of the solvent.
  1. Assertion: The water pouch of instant cold pack for treating athletic injuries breaks when squeezed and NH4N03 dissolves thus lowering the temperature.
Reason: Addition of non-volatile solute into solvent results into depression of freezing point of solvent.
  1. Assertion: If a non-volatile solute is mixed in a solution then elevation in boiling point and depression in freezing point both wiII be same.
Reason: Elevation in boiling point and depression in freezing point both depend on number of particles of solute.
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Q 27Case study (4 Marks)4 Marks
Read the passage given below and answer the following questions:
According to Raoult's law, the partial pressure of two components of the solution maybe given as:
$\text{P}_\text{A}=\stackrel{{0}}{\hbox{PA }}\text{x}_\text{A}$ and $\text{P}_\text{B}=\stackrel{{0}}{\hbox{PB }}\text{x}_\text{B}$
For an ideal solution (obeys Raoult's law always)
$\Delta\text{H}_\text{mix}=0,\Delta\text{mix}=0$
All solutions do not obey Raoults law over entire range of concentration. These are known as non-ideal solutions.
For non-ideal solutions, $\text{P}_\text{A}\not=\stackrel{{0}}{\hbox{PA }}\text{x}_\text{A}$ or $\text{P}_\text{B}\not=\stackrel{{0}}{\hbox{PB }}\text{x}_\text{B}$
Positive deviation $\Rightarrow\text{P}_\text{A}>\stackrel{{0}}{\hbox{PA }}\text{x}_\text{A}$ and $\text{P}_\text{B}>\stackrel{{0}}{\hbox{PB }}\text{x}_\text{B}$
Negative deviation $\text{P}_\text{A}<\stackrel{{0}}{\hbox{PA }}\text{x}_\text{A}$ and $\text{P}_\text{B}\stackrel{{0}}{\hbox{PB }}\text{x}_\text{B}$
A statement of assertion followed by a statement ofreason is given. Choose the correct answer out of the following choices.
  1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
  2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  3. Assertion is correct statement but reason is wrong statement.
  4. Assertion is wrong statement but reason is correct statement.
  1. Assertion: An ideal solution obeys Raoult's law.
Reason: In an ideal solution, solute-solute as well as solvent-solvent interactions are similar to solute-solvent interactions.
  1. Assertion: Acetone and aniline show negative deviations.
Reason: H-bonding between acetone and aniline is stronger than that between acetone-acetone and aniline-aniline.
  1. Assertion: Azeotropic mixtures are formed only by non-ideal solutions and they may have boiling points either greater than both the components or lesser than both the components.
Reason: The composition of the vapour phase is same as that of the liquid phase of an azeotropic mixture.
  1. Assertion: The solutions which show negative deviations from Raoult's law are called maximum boiling azeotropes.
Reason: 68% nitric acid and 32% water by mass fonn maximum boiling azeotrope.
  1. Assertion: $\Delta\text{H}_{\text{mix}}$ mix and $\Delta\text{V}_{\text{mix}}$ are positive for an ideal solution.
Reason: The interactions between the particles of the components of an ideal solution are almost identical as between particles in the liquids.
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Q 28Case study (4 Marks)4 Marks
Read the passage given below and answer the following questions:
The solubility of gases increases with increase of pressure. William Henry made a systematic investigation of the solubility of a gas in a liquid. According to Henry's law "the mass of a gas dissolved per unit volume of the solvent at constant temperature is directly proportional to the pressure of the gas in equilibrium with the solution". Dalton during the same period also concluded independently that the solubility of a gas in a ti quid solution depends upon the partial pressure of the gas. If we use the mole fraction of gas in the solution as a measure of its solubility, then Henry's law can be modified as "the partial pressure of the gas in the vapour phase is directly proportional to the mole fraction of the gas in the solution"
The following questions are multiple choice questions. Choose the most appropriate answer:
  1. Henry's law constant for the solubility of methane in benzene at $298K$ is $4.27 x 10^5$mm Hg. The solubility of methane in benzene at $298K$ under $760$mm Hg is:
  1. $4.27 \times 10^{-5}$
  2. $1.78 \times 10^{-3}$
  3. $4.27 \times 10^{-3}$
  4. $1.78 \times 10^{-5}$
  1. The partial pressure of ethane over a saturated solution containing $6.56 \times 10^{-2}g$ of ethane is I bar. If the solution contains $5.00 \times 10^{-2}g$ of ethane then what will be the partial pressure (in bar) of the gas?
  1. 0.762
  2. 1.312
  3. 3.81
  4. 5.0
  1. $K_H (K$ bar$)$ values for $Ar_{(g),} CO_{2(g),} HCHO_{(g)}$ and $CH_{4(g)}$ are $40.39, 1.67, 1.83 \times 10^{-5}$ and $0.413$ respectively. Arrange these gases in the order of their increasing solubility. Arrange these gases in the order of their increasing solubility.
  1. $HCHO < CH_4 < CO_2 < Ar$
  2. $HCHO < CO_2 < CH_4 < Ar$
  3. $Ar < CO_2 < CH_4 < HCHO$
  4. $Ar < CH_4 < CO_2 < HCHO$
  1. When a gas is bubbled through water at $298K$, a very dilute solution of the gas is obtained. Henry's law constant for the gas at 298K is 150 kbar. If the gas exerts a partial pressure of $2$ bar, the number of millimoles of the gas dissolved in IL of water is:
  1. $0.55$
  2. $0.87$
  3. $0.37$
  4. $0.66$
  1. Which of the following statements is correct?
  1. $K_H$ increases with increase of temperature.
  2. $K_H$ decreases with increase of temperature.
  3. $K_H$ remains constant with increase of temperature.
  4. $K_H$ first increases then decreases, with increase of temperature.
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Q 29Case study (4 Marks)4 Marks
Read the passage given below and answer the following questions:
If some solute is added to a solvent, the boiling point of solution increases. This is known as elevation in baiting point.
$\Delta\text{T}_\text{b}=\text{K}_\text{b}\text{m}$ where, $K_b =$ Molal elevation constant,
$\Delta\text{T}_\text{b}\propto\text{m}$
Hence, it is a colligative property,
Also, $\text{K}_\text{b}=\frac{\text{MRT}^2_\text{b}}{\Delta\text{Vap}\text{H}\times1000}$
where, $M =$ Molar mass of solvent,
$\Delta\text{vap}$ $H = $Enthalpy of vaporisation,
Molar mass can also be calculated using elevation in boiling point.
$\text{M}_\text{B}=\frac{\text{K}_\text{B}\times\text{W}_\text{B}\times1000}{\Delta\text{T}_\text{b}\times\text{W}_\text{A}}$
A statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
  1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
  2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  3. Assertion is correct statement but reason is wrong statement.
  4. Assertion is wrong statement but reason is correct statement.
  1. Assertion: In a pressure cooker, the water is brought to boil. The cooker is then removed from the stove. Now on removing the lid of pressure cooker, the water starts boiling again.
Reason: The impurities in water bring down its boiling point.
  1. Assertion: On dissolving $3.24g$ of sulphur in $40g$ of benzene, boiling point of solution get higher than that of benzene by $0.081K$, then the formula of sulphur is $S_8. (K_b$ for benzene $= 2.53K\ kg\ mol^{-1})$
Reason: Molecular mass of sulphur comes out to be $253.$
  1. Assertion: When sugar is added to water, boiling point of water increases.
Reason: When a non-volatile solute is added to a solvent, elevation in boiling point is observed.
  1. Assertion: Cooking time in pressure cookers is reduced.
Reason: Boiling point inside the pressure cooker in raised.
  1. Assertion: Elevation in boiling point of two isotonic solutions is same.
Reason: Boiling point depends upon the concentration of the solute.
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Q 30Case study (4 Marks)4 Marks
Read the passage given below and answer the following questions:
The properties of the solutions which depend only on the number of solute particles but not on the nature of the solute are called colligative properties. Relative lowering in vapour pressure is also an example of colligative properties. For an experiment, sugar solution is prepared, for which lowering in vapour pressure was found to be 0.061 mm of Hg. (Vapour pressure of water at 20° C is 17.5 mm of Hg)
The following questions are multiple choice questions. Choose the most appropriate answer:
  1. Relative lowering of vapour pressure for the given solution is.
  1. 0.00348
  2. 0.061
  3. 0.122
  4. 1.75
  1. The vapour pressure (mm of Hg) of solution will be.
  1. 17.5
  2. 0.61
  3. 17.439
  4. 0.00348
  1. Mole fraction of sugar in the solution is.
  1. 0.00348
  2. 0.9965
  3. 0.061
  4. 1.75
  1. If weight of sugar taken is 5g in 108g of water, then molar mass of sugar will be.
  1. 358
  2. 120
  3. 240
  4. 400
  1. The vapour pressure (mm of Hg) of water at 293K when 25g of glucose is dissolved in 450g of water is.
  1. 17.2
  2. 17.4
  3. 17.120
  4. 17.02
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Q 315 Marks Questions5 Marks
  1. What type of deviation is shown by a mixture of ethanol and acetone? Give reason.
  2. A solution of glucose (molar mass = $180 g\ mol^{–1}$) in water is labelled as $10\%$ (by mass). What would be the molality and molarity of the solution?
(Density of solution = $1.2 g\ mL^{–1}$).
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Q 325 Marks Questions5 Marks
  1. A $10\%$ solution (by mass) of sucrose in water has a freezing point of $269.15 K$. Calculate the freezing point of $10\%$ glucose in water if the freezing point of pure water is $273.15 K$. Given:
(Molar mass of sucrose = $342 g mol^{-1}$)

(Molar mass of glucose = $180 g mol^{-1}$)
  1. Define the following terms:
  1. Molality (m)
  2. Abnormal molar mass
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Q 335 Marks Questions5 Marks
  1. $30 g$ of urea $(M = 60 g mol^{-1})$ is dissolved in 846 g of water. Calculate the vapour pressure of water for this solution if vapour pressure of pure water at $298 K$ is $23.8$ mm Hg.
  2. Write two differences between ideal solutions and non-ideal solutions.
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Q 345 Marks Questions5 Marks
  1. Define the following terms:
  1. Molarity.
  2. Molal elevation constant(Kb).
  1. A solution containing 15 g urea (molar mass = $60 g\ mol^{–1}$​​​​​​​) per litre of solution in water has the same osmotic pressure (isotonic) as a solution of glucose (molar mass = $180 g\ mol^{–1}​​​​​​​$) in water. Calculate the mass of glucose present in one litre of its solution.
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Q 355 Marks Questions5 Marks
  1. State Raoult’s law for a solution containing volatile components.
How does Raoult’s law become a special case of Henry’s law?
  1. $1.00\ g$ of a non-electrolyte solute dissolved in $50\ g$ of benzene lowered the freezing point of benzene by $0.40\ K$. Find the molar mass of the solute. $(K_f$ for benzene$= 5.12\ kg\ mol^{-1})$.
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