HOTs Solutions Class 12 Chemistry

Please refer to Solutions HOTs Class 12 Chemistry provided below with solutions. All HOTs for Class 12 Chemistry with answers provided below have been designed as per the latest syllabus and examination petter issued by CBSE, NCERT, KVS. Students of Standard 12 Chemistry should learn the solved HOTS for Class 12 Chemistry provided below to gain better marks in examinations.

Solutions Class 12 Chemistry HOTs

(MULTIPLE CHOICE QUESTION)

Question. Low concentration of oxygen in the blood and tissues of people living at high altitude is due to ____________.
a. low temperature
b. low atmospheric pressure
c. high atmospheric pressure
d. both low temperature and high atmospheric pressure

Question. At equilibrium the rate of dissolution of a solid solute in a volatile liquid solvent is __________.
a. less than the rate of crystallisation
b. greater than the rate of crystallisation
c. equal to the rate of crystallisation
d. zero

Question. An unripe mango placed in a concentrated salt solution to prepare pickle, shrivels because _____________.
a. it gains water due to osmosis.
b. it loses water due to reverse osmosis.
c. it gains water due to reverse osmosis.
d. it loses water due to osmosis.

Question. Maximum amount of a solid solute that can be dissolved in a specified amount of a given liquid solvent does not depend upon ____________.
a. Temperature
b. Nature of solute
c. Pressure
d. Nature of solvent

Question. Which of the following units is useful in relating concentration of solution with its vapour pressure?
a. mole fraction
b. parts per million
c. mass percentage
d. molality

Question. The values of Van’t Hoff factors for KCl, NaCl and K₂SO₄, respectively, are _____________.
a. 2, 2 and 2
b. 2, 2 and 3
c. 1, 1 and 2
d. 1, 1 and 1

Question. Considering the formation, breaking and strength of hydrogen bond, predict which of the following mixtures will show a positive deviation from Raoult’s law?
a. Methanol and acetone.
b. Chloroform and acetone.
c. Nitric acid and water.
d. Phenol and aniline.

Question. 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?
a. Sugar crystals in cold water.
b. Sugar crystals in hot water.
c. Powdered sugar in cold water.
d. Powdered sugar in hot water.

Question. The value of Henry’s constant KH is _____________.
a. greater for gases with higher solubility.
b. greater for gases with lower solubility.
c. constant for all gases.
d. not related to the solubility of gases.

Question. The unit of ebulioscopic constant is _______________.
a. K kg /mol or K (molality)^–1
b. mol kg/ K or K^–1(molality)
c. kg mol^–1 K^–1 or K^–1(molality)^–1
d. K mol kg^–1 or K (molality)

Question. A beaker contains a solution of substance ‘A’. Precipitation of substance ‘A’ takes place when small amount of ‘A’ is added to the solution. The solution is _________.
a. saturated
b. supersaturated
c. unsaturated
d. concentrated

Question. Value of Henry’s constant KH ____________.
a. increases with increase in temperature.
b. decreases with increase in temperature.
c. remains constant.
d. first increases then decreases.

Question. At a given temperature, osmotic pressure of a concentrated solution of a substance_____________.
a. is higher than that at a dilute solution.
b. is lower than that of a dilute solution.
c. is same as that of a dilute solution.
d. cannot be compared with osmotic pressure of dilute solution.

Question. We have three aqueous solutions of NaCl labeled as ‘A’, ‘B’ and ‘C’ with concentrations 0.1M, 0.01M and 0.001M, respectively. The value of van’t Hoff factor for these solutions will be in the order______.
a. iA < iB < iC
b. iA > iB > iC
c. iA = iB = iC
d. iA < iB > Ic

Question. Which of the following statements is false?
a. Units of atmospheric pressure and osmotic pressure are the same.
b. In reverse osmosis, solvent molecules move through a semipermeable membrane from a region of lower concentration of solute to a region of higher concentration.
c. The value of molal depression constant depends on nature of solvent.
d. Relative lowering of vapour pressure, is a dimensionless quantity.

Question. Which of the following aqueous solutions should have the highest boiling point?
a. 1.0 M NaOH
b. 1.0 M Na₂SO₄
c. 1.0 M NH₄NO₃
d. 1.0 M KNO₃

Question. In comparison to a 0.01 M solution of glucose, the depression in freezing point of a 0.01 M MgCl₂ solution is _____________.
a. the same
b. about twice
c. about three times
d. about six times

Question. If two liquids A and B form minimum boiling azeotrope at some specific composition then_______________.
a. A–B interactions are stronger than those between A–A or B–B.
b. vapour pressure of solution increases because more number of molecules of liquids A and B can escape from the solution.
c. vapour pressure of solution decreases because less number of molecules of only one of the liquids escape from the solution.
d. A–B interactions are weaker than those between A–A or B–B.

Question. Colligative properties depend on ____________.
a. the nature of the solute particles dissolved in solution.
b. the number of solute particles in solution.
c. the physical properties of the solute particles dissolved in solution.
d. the nature of solvent particles.

Question. Which of the following statements is false?
a. 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 Π = CRT ( where C is the molarity of the solution).
c. Decreasing order of osmotic pressure for 0.01 M aqueous solutions of barium chloride, potassium chloride, acetic acid and sucrose is BaCl₂ > KCl > CH₃COOH > 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.

ASSERTION -REASON TYPE

A statement of assertion is followed by a statement of reason. Mark the correct choice from the options given below:
(a) Both assertion and reason are true and reason is the correct explanation of assertion.
(b) Both assertion and reason are true but reason is not the correct explanation of assertion.
(c) Assertion is true but reason is false.
(d) Both assertion and reason are false.

Question. Assertion : Osmosis does not take place in two isotonic solutions separated by semi-permeable membrane.
Reason : Isotonic solutions have same osmotic pressure.

Question. Assertion : Two liquids nitric acid and water form a maximum boiling azeotrope when mixed in the ratio of 68% and 32% respectively.
Reason : Interaction between nitric acid and water are stronger than nitric acid – nitric acid interactions and water – water interactions.

Question. Assertion : Lowering of vapour pressure is not dependent on the number of species present in the solution.
Reason : Lowering of vapour pressure and relative lowering of vapour pressure are colligative properties.

Question. Assertion : In an ideal solution, Δmix H is zero.
Reason : In an ideal solution, A – B interactions are lower than A-A and B-B interactions.

Question. Assertion : 1 M solution of KCl has greater osmotic pressure than 1 M solution of glucose at same temperature.
Reason : In solution KCl dissociates to produce more number of particles.

One – word answers

Question. Liquids A and B on mixing produce a warm solution. Which type of deviation from Raoult’s law is shown?
Answer.  Negative deviation

Question. Liquid ‘Y’ has higher vapour pressure than liquid ’ X’ . Which of them will have higher boiling point.
Answer.  X

Question. Under what condition Van’t Hoff factor is less than 1?
Answer.  Association