NCERT Exemplar solutions for Chemistry [English] Class 12 chapter 2 - Solutions [Latest edition]

Which of the following units is useful in relating concentration of solution with its vapour pressure?

On dissolving sugar in water at room temperature solution feels cool to touch. Under which of the following cases dissolution of sugar will be most rapid?

At equilibrium the rate of dissolution of a solid solute in a volatile liquid solvent is ______.

A beaker contains a solution of the substance ‘A’. Precipitation of substance ‘A’ takes place when a small amount of ‘A’ is added to the solution. The solution is ______.

Maximum amount of a solid solute that can be dissolved in a specified amount of a given liquid solvent does not depend upon ______.

Low concentration of oxygen in the blood and tissues of people living at high altitude is due to ______.

Considering the formation, breaking and strength of hydrogen bond, predict which of the following mixtures will show a positive deviation from Raoult’s law?

Colligative properties depend on ______.

Which of the following aqueous solutions should have the highest boiling point?

The unit of ebulioscopic constant is ______.

In comparison to a 0.01 m solution of glucose, the depression in freezing point of a 0.01 m MgCl₂ solution is ______.

An unripe mango placed in a concentrated salt solution to prepare pickle, shrivels because ______.

At a given temperature, osmotic pressure of a concentrated solution of a substance ______.

Which of the following statements is false?

The values of Van’t Hoff factors for KCl, NaCl and K₂SO₄, respectively, are ______.

Which of the following statements is false?

Value of Henry’s constant K_H ______.

The value of Henry's constant K_H is ______.

Consider the figure and mark the correct option.

We have three aqueous solutions of NaCl labelled as ‘A’, ‘B’ and ‘C’ with concentrations 0.1 M, 0.01 M and 0.001 M, respectively. The value of van’t Hoff factor for these solutions will be in the order ______.

On the basis of information given below mark the correct option.

(A) In bromoethane and chloroethane mixture intermolecular interactions of A–A and B–B type are nearly same as A–B type interactions.

(B) In ethanol and acetone mixture A–A or B–B type intermolecular interactions are stronger than A–B type interactions.

(C) In chloroform and acetone mixture A–A or B–B type intermolecular interactions are weaker than A–B type interactions.

Two beakers of capacity 500 mL were taken. One of these beakers, labelled as “A”, was filled with 400 mL water whereas the beaker labelled “B” was filled with 400 mL of 2 M solution of NaCl. At the same temperature both the beakers were placed in closed containers of same material and same capacity as shown in figure.

At a given temperature, which of the following statement is correct about the vapour pressure of pure water and that of NaCl solution.

If two liquids A and B form minimum boiling azeotrope at some specific composition then ______.

4 L of 0.02 M aqueous solution of NaCl was diluted by adding one litre of water. The molality of the resultant solution is ______.

On the basis of information given below mark the correct option.
On adding acetone to methanol some of the hydrogen bonds between methanol molecules break.

K_H value for \[\ce{Ar(g)}\], \[\ce{CO2(g)}\], \[\ce{HCHO (g)}\] and \[\ce{CH4(g)}\] are 40.39, 1.67, 1.83 × 10^–5 and 0.413 respectively. Arrange these gases in the order of their increasing solubility.

Which of the following factor(s) affect the solubility of a gaseous solute in the fixed volume of liquid solvent?

(a) nature of solute

(b) temperature

(c) pressure

(i) (a) and (c) at constant T

(ii) (a) and (b) at constant P

(iii) (b) and (c) only

(iv) (c) only

Intermolecular forces between two benzene molecules are nearly of same strength as those between two toluene molecules. For a mixture of benzene and toluene, which of the following are not true?

(i) ∆_mix H = zero

(ii) ∆_mix V = zero

(iii) These will form minimum boiling azeotrope.

(iv) These will not form ideal solution.

Relative lowering of vapour pressure is a colligative property because:

(i) It depends on the concentration of a non electrolyte solute in solution and does not depend on the nature of the solute molecules.

(ii) It depends on number of particles of electrolyte solute in solution and does not depend on the nature of the solute particles.

(iii) It depends on the concentration of a non electrolyte solute in solution as well as on the nature of the solute molecules.

(iv) It depends on the concentration of an electrolyte or nonelectrolyte solute in solution as well as on the nature of solute molecules.

Van’t Hoff factor i is given by the expression:

(i)  i = `"Normal molar mass"/"Abnormal molar mass"`

(ii)  i = `"Abnormal molar mass"/"Normal molar mass"`

(iii) i = `"Observed colligative property"/"Calculated colligative property"`

(iv) i =  `"Calculated colligative property"/"Observed colligative property"`

Isotonic solutions must have the same:

(i) solute

(ii) density

(iii) elevation in boiling point

(iv) depression in freezing point

Which of the following binary mixtures will have same composition in liquid and vapour phase?

(i) Benzene - Toluene

(ii) Water-Nitric acid

(iii) Water-Ethano

(iv) n-Hexane - n-Heptane

In isotonic solutions:

(i) Solute and solvent both are same.

(ii) Osmotic pressure is same.

(iii) Solute and solvent may or may not be same.

(iv) Solute is always same solvent may be different.

For a binary ideal liquid solution, the variation in total vapour pressure versus composition of solution is given by which of the curves?

Colligative properties are observed when:

(i) a non volatile solid is dissolved in a volatile liquid.

(ii) a non volatile liquid is dissolved in another volatile liquid.

(iii) a gas is dissolved in non volatile liquid.

(iv) a volatile liquid is dissolved in another volatile liquid.

Components of a binary mixture of two liquids A and B were being separated by distillation. After some time separation of components stopped and composition of vapour phase became same as that of liquid phase. Both the components started coming in the distillate. Explain why this happened.

Explain why on addition of 1 mol of NaCl to 1 litre of water, the boiling point of water increases, while addition of 1 mol of methyl alcohol to one litre of water decreases its boiling point.

Explain the solubility rule “like dissolves like” in terms of intermolecular forces that exist in solutions.

Concentration terms such as mass percentage, ppm, mole fraction and molality are independent of temperature, however molarity is a function of temperature. Explain.

What is the significance of Henry’s Law constant K_H?

Why are aquatic species more comfortable in cold water in comparison to warm water?

Explain the following phenomena with the help of Henry’s law.

Painful condition known as bends.

Explain the following phenomena with the help of Henry’s law.

Feeling of weakness and discomfort in breathing at high altitude.

Why soda water bottle kept at room temperature fizzes on opening?

Why is the vapour pressure of an aqueous solution of glucose lower than that of water?

How does sprinkling of salt help in clearing the snow covered roads in hilly areas? Explain the phenomenon involved in the process.

What is “semi permeable membrane”?

Give an example of a material used for making semipermeable membrane for carrying out reverse osmosis.

Match the items given in Column I and Column II.

Match the items given in Column I with the type of solutions given in Column II.

Match the laws given in Column I with expresions given in Column II.

Match the terms given in Column I with expressions given in Column II.

Assertion: Molarity of a solution in liquid state changes with temperature.

Reason: The volume of a solution changes with change in temperature.

Assertion: When methyl alcohol is added to water, the boiling point of water increases.

Reason: When a volatile solute is added to a volatile solvent elevation in boiling point is observed.

Assertion: When NaCl is added to water a depression in freezing point is observed.

Reason: The lowering of vapour pressure of a solution causes depression in the freezing point.

Assertion: When a solution is separated from the pure solvent by a semipermeable membrane, the solvent molecules pass through it from pure solvent side to the solution side.

Reason: Diffusion of solvent occurs from a region of high concentration solution to a region of low concentration solution.

Define the following modes of expressing the concentration of a solution. Which of these modes are independent of temperature and why?

w/w (mass percentage)

Define the following modes of expressing the concentration of a solution. Which of these modes are independent of temperature and why?

V/V (volume percentage)

Define the following modes of expressing the concentration of a solution. Which of these modes are independent of temperature and why?

(iii) w/V (mass by volume percentage)

Define the following modes of expressing the concentration of a solution. Which of these modes are independent of temperature and why?

ppm. (parts per million)

Define the following modes of expressing the concentration of a solution. Which of these modes are independent of temperature and why?

x (mole fraction)

Define the following modes of expressing the concentration of a solution. Which of these modes are independent of temperature and why?

M (Molarity)

Define the following modes of expressing the concentration of a solution. Which of these modes are independent of temperature and why?

m (Molality)

Using Raoult’s law explain how the total vapour pressure over the solution is related to mole fraction of components in the following solutions.

\[\ce{CHCl3(l) and CH2Cl2(l)}\]

Using Raoult’s law explain how the total vapour pressure over the solution is related to mole fraction of components in the following solutions.

\[\ce{NaCl(s) and H2O(l)}\]

Explain the terms ideal and non-ideal solutions in the light of forces of interactions operating between molecules in liquid solutions.

Why is it not possible to obtain pure ethanol by fractional distillation? What general name is given to binary mixtures which show deviation from Raoult’s law and whose components cannot be separated by fractional distillation. How many types of such mixtures are there?

When kept in water, raisin swells in size. Name and explain the phenomenon involved with the help of a diagram. Give three applications of the phenomenon.

Discuss biological and industrial importance of osmosis.

How can you remove the hard calcium carbonate layer of the egg without damaging its semiprermiable membrane? Can this egg be inserted into a bottle with a narrow neck without distorting its shape? Explain the process involved.

Why is the mass determined by measuring a colligative property in case of some solutes abnormal ? Discuss it with the help of Van’t Hoff factor.