Solutions Most Important MCQ’s for Board Exams | Class 12 Chemistry

In This Post we Are Discussing About Solutions Class 12 Chemistry Most Important MCQ’s for Board Exams 2025, As we all know, MCQs play a crucial role at the beginning of the Class 12 Board Exam paper. A strong start with the right MCQs can set a positive tone for the entire exam and pave the way for achieving the best possible score. In this post, we’re sharing the most important MCQs for Chemistry Solution Chapter that will help you kick off your exam with confidence and success!

So Read Whole Article and in The Bottom You Will Get Solutions Most Important MCQ’s for Class 12 Board Exams 2025 PDF Link too.

Score Full Marks in Chemistry

1. Low concentration of oxygen in the blood and tissues of people living at high altitude is due to:
a) High atmospheric pressure
b) Low temperature
c) Low atmospheric pressure
d) Both low temperature and high atmospheric pressure
Answer: c) Low atmospheric pressure

2. Value of Henry’s constant KH:
a) Increases with decrease in temperature
b) Decreases with increase in temperature
c) Increases with increase in temperature
d) Remains constant
Answer: c) Increases with increase in temperature

3. An azeotropic mixture of two liquids will have a boiling point lower than either of the two liquids when it:
a) Shows a negative deviation from Raoult’s law
b) Forms an ideal solution
c) Shows a positive deviation from Raoult’s law
d) Is saturated
Answer: c) Shows a positive deviation from Raoult’s law

4. An azeotropic mixture of two liquids has a boiling point higher than either of the two liquids when it:
a) Shows large negative deviation from Raoult’s law
b) Shows no deviation from Raoult’s law
c) Shows large positive deviation from Raoult’s law
d) Obeys Raoult’s law
Answer: a) Shows large negative deviation from Raoult’s law

5. 1 mole of liquid A and 2 moles of liquid B make a solution having a total vapor pressure of 40 torr. The vapor pressure of pure A and pure B are 45 torr and 30 torr respectively. The above solution:
a) Is an ideal solution
b) Shows positive deviation
c) Shows negative deviation
d) Is a maximum boiling azeotrope
Answer: b) Shows positive deviation

6. Van’t Hoff factor values for KCl and K₂SO₄ respectively are:
a) 1 and 2
b) 2 and 3
c) 2 and 2
d) 2 and 4
Answer: b) 2 and 3

7. The colligative property used for the determination of molar mass of polymers and proteins is:
a) Osmotic pressure
b) Depression in freezing point
c) Relative lowering in vapor pressure
d) Elevation in boiling point
Answer: a) Osmotic pressure

8. Which of the following colligative properties is used to find the molar mass of proteins?
a) Osmotic pressure
b) Elevation in boiling point
c) Depression in freezing point
d) Relative lowering of vapor pressure
Answer: a) Osmotic pressure

9. Isotonic solutions have:
a) Same osmotic pressure
b) Same boiling point
c) Same melting point
d) Same vapor pressure
Answer: a) Same osmotic pressure

10. A compound undergoes complete tetramerization in a given organic solvent. The Van’t Hoff factor ‘i’ is:
a) 4.0
b) 0.25
c) 0.125
d) 2.0
Answer: a) 4.0

11. A compound CaCl₂.6H₂O undergoes complete dissociation in water. The Van’t Hoff factor ‘i’ is:
a) 9
b) 6
c) 3
d) 4
Answer: c) 3

12. If molality of a dilute solution is doubled, the value of the molal elevation constant (Kb) will be:
a) Halved
b) Doubled
c) Tripled
d) Unchanged
Answer: d) Unchanged

13. Which of the following aqueous solutions will have the highest boiling point?
a) 1.0 M KCl
b) 1.0 M K₂SO₄
c) 2.0 M KCl
d) 2.0 M K₂SO₄
Answer: d) 2.0 M K₂SO₄

14. Out of the following 1.0 M aqueous solutions, which one will show the largest freezing point depression?
a) NaCl
b) Na₂SO₄
c) C₆H₁₂O₆
d) Al₂(SO₄)₃
Answer: d) Al₂(SO₄)₃