- Amal Augustine
- January 31, 2026
Master Molar Mass Determination Numerical MCQs Solutions to Boost NEET, JEE, & CUET
Molar mass determination numerical MCQs solutions play a crucial role in Class 11 and Class 12 Chemistry, especially in chapters related to solutions, colligative properties, and gaseous states. Many competitive exams such as NEET, JEE Main, and JEE Advanced frequently include questions where aspirants must calculate molar mass using numerical data. Therefore, mastering molar mass determination numerical MCQs solutions is essential for both board exams and entrance tests.
At its core, molar mass determination involves calculating the molecular weight of a solute using experimentally observed data like freezing point depression, boiling point elevation, osmotic pressure, or relative lowering of vapour pressure. In most objective-type exams, these concepts are tested through numerical MCQs, making molar mass determination numerical MCQs solutions an indispensable practice area.
One of the most common methods used in molar mass determination numerical MCQs solutions is freezing point depression. According to colligative properties, the depression in freezing point depends on the number of solute particles present in the solution. By applying the formula
ΔTf=Kf×m\Delta T_f = K_f \times m,
apirants can easily calculate molality and then determine the molar mass. Many molar mass determination numerical MCQs solutions are based on this principle, especially for non-electrolytes.
Another frequently tested approach in molar mass determination numerical MCQs solutions is boiling point elevation. Here, the increase in boiling point of a solvent is measured after adding a known mass of solute. Using the relation
ΔTb=Kb×m\Delta T_b = K_b \times m,
the molar mass of the solute can be calculated. Competitive exams often design tricky molar mass determination numerical MCQs solutions by including association or dissociation effects, which students must handle carefully.
Osmotic pressure is another powerful tool used in molar mass determination numerical MCQs solutions. This method is especially useful for dilute solutions and macromolecules like proteins and polymers. The formula
π=CRT\pi = CRT
directly connects osmotic pressure with molar mass. Many higher-difficulty molar mass determination numerical MCQs solutions in NEET and JEE rely on this concept.
An important challenge in molar mass determination numerical MCQs solutions arises when the solute undergoes association (like acetic acid dimerization) or dissociation (like electrolytes). In such cases, the Van’t Hoff factor (i) must be introduced. Ignoring this factor can lead to incorrect answers, which is why understanding its role is vital while solving molar mass determination numerical MCQs solutions.
Aspirants should also note that relative lowering of vapour pressure is directly proportional to the mole fraction of solute. This concept is commonly used in molar mass determination numerical MCQs solutions involving Raoult’s law. These questions usually require careful substitution of values rather than lengthy calculations.
From an exam strategy point of view, practicing molar mass determination numerical MCQs solutions improves speed, accuracy, and confidence. Many MCQs follow repeated patterns, so familiarity with standard numerical types helps students quickly identify the correct formula and eliminate wrong options.
In NEET and JEE exams, molar mass determination numerical MCQs solutions are often integrated with assertion–reason questions and multi-step numericals, increasing their difficulty level. Hence, conceptual clarity combined with regular practice is essential.
30 Molar Mass Determination Numerical MCQs Solutions
1. An ideal solution is formed when its components
-
can be converted into gases
-
obey Raoult’s law
-
have no change of volume
-
have zero heat of mixing
Options:
A. 1 only
B. 2, 3 and 4
C. 2 only
D. 3 and 4 only
Answer: B
2. X is a non-volatile solute and Y is a volatile solvent.
The correct order of vapor pressures is**
Options:
A. P₃ < P₁ < P₂
B. P₂ < P₃ < P₁
C. P₁ < P₃ < P₂
D. P₂ < P₁ < P₃
Answer: D
3. What is the freezing point of a solution containing 8.1 g HBr in 100 g water (90% ionized)?
(Kf=1.86K_f = 1.86)
Options:
A. 0.85°C
B. −3.53°C
C. 0.3°C
D. 0°C
Answer: B
4. Which of the following increases with increase in temperature?
Options:
A. Surface tension
B. Viscosity
C. Molality
D. Vapour pressure
Answer: D
5. Difference between boiling point and freezing point of solution is 105°C.
Weight of sucrose is**
Options:
A. 34.2 g
B. 68.4 g
C. 342 g
D. 72 g
Answer: D
6. A 0.0020 m solution of [Co(NH₃)₅(NO₂)]Cl freezes at −0.00732°C.
Number of ions produced =**
Options:
A. 3
B. 4
C. 2
D. 1
Answer: C
7. Correct order of freezing point (1 M solutions)
Options:
A. Sucrose > KCl > BaCl₂ > AlCl₃
B. AlCl₃ > BaCl₂ > KCl > Sucrose
C. BaCl₂ > KCl > AlCl₃ > Sucrose
D. KCl > BaCl₂ > AlCl₃ > Sucrose
Answer: A
8. Value of PB0P_B^0 is
Options:
A. 940
B. 405
C. 90
D. None of these
Answer: C
9. A solution with negative deviation is
Options:
A. Ethanol–Acetone
B. Chlorobenzene–Bromobenzene
C. Chloroform–Acetone
D. Benzene–Toluene
Answer: C
10. Mole fraction of B in vapour phase is
Options:
A. 0.6
B. 0.5
C. 0.8
D. 0.4
Answer: D
11. Correct sequence of colligative effects
Options:
A. ΔP: 3 < 2 < 1
B. ΔTᵦ: 1 < 2 < 3
C. ΔTᵦ: 3 < 2 < 1
D. None of these
Answer: D
12. Molar mass of organic compound is closest to
Options:
A. 61 g/mol
B. 63 g/mol
C. 65 g/mol
D. 67 g/mol
Answer: B
13. Correct statements for ideal solution
Options:
A. 3 and 4
B. 1 and 4
C. 1 and 2
D. 2 and 3
Answer: C
14. Freezing point depression of 0.02 m urea is
Options:
A. 0.37°C
B. 0.185°C
C. 0.74°C
D. 0°C
Answer: A
15. Ostwald–Walker method measures
Options:
A. Relative lowering of vapour pressure
B. Lowering of vapour pressure
C. Vapour pressure of solvent
D. All of these
Answer: A
16. Value of equilibrium constant K is
Options:
A. 50
B. 100
C. 166.6
D. 150
Answer: B
17. Vapour pressure after adding glucose is
Options:
A. 17.675 mmHg
B. 15.750 mmHg
C. 16.500 mmHg
D. 17.325 mmHg
Answer: D
18. Maximum lowering of vapour pressure is for
Options:
A. 0.1 M Glucose
B. 0.1 M BaCl₂
C. 0.1 M MgSO₄
D. 0.1 M NaCl
Answer: B
19. Relative lowering of vapour pressure equals
Options:
A. Solute molecules / total molecules
B. Solvent / solute
C. Solute / solvent
D. Total molecules
Answer: A
20. Solution obeying Raoult’s law is
Options:
A. Normal solution
B. Molar solution
C. Ideal solution
D. Saturated solution
Answer: C
21. Molecular weight of solute is
Options:
A. 206
B. 302
C. 350
D. 276
Answer: C
22. Vapour pressure of solution is
Options:
A. 19
B. 19.602
C. 19.402
D. 19.202
Answer: B
23. Correct relation is
Options:
A. Ps−XAPB0P_s – X_A P_B^0
B. PB0=PsXAP_B^0 = P_s X_A
C. Ps=XBPB0P_s = X_B P_B^0
D. PB0=PsXBP_B^0 = P_s X_B
Answer: C
24. Molal elevation constant is
Options:
A. 1.0 K kg mol⁻¹
B. 10 K kg mol
C. 10 K g mol⁻¹
D. 10 K kg mol⁻¹
Answer: D
25. Lowering in freezing point is
Options:
A. 0.56 K
B. 1.12 K
C. −0.56 K
D. −1.12 K
Answer: B
26. Fractional distillation depends on
Options:
A. Freezing point
B. Boiling point
C. Melting point
D. Solubility
Answer: B
27. Required mass of urea is
Options:
A. 3.6 g
B. 2 g
C. 7.2 g
D. 6.0 g
Answer: C
28. Molecular mass of solid is
Options:
A. 58
B. 180
C. 170
D. 145
Answer: C
29. Entropy change is
Options:
A. 20.13
B. 2.198
C. 2.98
D. 21.98
Answer: D
30. Increase in temperature of water is
Options:
A. 1.2 K
B. 2.4 K
C. 4.8 K
D. 6.6 K
Answer: B
Molar Mass Determination Numerical MCQs Solutions
To summarize, molar mass determination numerical MCQs solutions form a high-weightage and scoring section in physical chemistry. Whether the question is based on freezing point depression, boiling point elevation, osmotic pressure, or vapour pressure lowering, a systematic approach ensures correct results. With consistent practice of molar mass determination numerical MCQs solutions, aspirants can significantly improve their performance in competitive exams and board examinations alike.
Amal Augustine is the founder of ExQuizMe, a dynamic learning and quiz platform built to make education engaging, competitive, and fun. A passionate learner and an academic achiever, Amal completed his schooling at Government HSS Manjapra, graduating with 92.5% in Computer Science. He later earned his degree from St. Stephen’s College, University of Delhi, one of India’s most prestigious arts and science institutions.
Currently, Amal is pursuing his Master’s degree at National Sun Yat-sen University, Taiwan, where he continues to deepen his interest in research and technology. Throughout his school and college years, he won 50+ national-level interschool and collegiate quiz competitions, was
Beyond academics, Amal Augustine is an avid reader of science journals, a dedicated research student, and a technology enthusiast who loves programming and exploring the world of Computer Science. Through ExQuizMe, he aims to make learning accessible, enjoyable, and empowering for students across the globe.