“Mole Concept” MCQ with Answer Explanation : NEET 2025.

11. How many molecules are in 2 moles of CO₂?
    a) 1.2 × 10²⁴
    b) 6.022 × 10²³
    c) 1.2044 × 10²⁴
    d) 12.044 × 10²³

Answer: a) 1.2 × 10²⁴

Explanation: Multiply the number of moles by Avogadro’s number: 2 moles × 6.022 × 10²³ molecules/mole.

12. If 1 mole of a substance has a mass of 10 g, what is its molar mass?
    a) 5 g/mol
    b) 10 g/mol
    c) 20 g/mol
    d) 15 g/mol

Answer: b) 10 g/mol

Explanation: The molar mass is the mass of one mole of the substance, which is given as 10 g.

13. What is the total number of moles in 50 g of KCl (Molar mass = 74.5 g/mol)?
    a) 0.67 moles
    b) 1.02 moles
    c) 0.75 moles
    d) 1.50 moles

Answer: a) 0.67 moles

Explanation: 50 g ÷ 74.5 g/mol ≈ 0.67 moles.

14. Which of the following is not a state function?
    a) Temperature
    b) Pressure
    c) Heat
    d) Volume

Answer: c) Heat

Explanation: Heat is not a state function; it depends on the path taken, unlike temperature, pressure, and volume.

15. What is the number of moles in 44 g of CO₂ (Molar mass = 44 g/mol)?
    a) 1 mole
    b) 2 moles
    c) 0.5 moles
    d) 3 moles

Answer: a) 1 mole

Explanation: 44 g ÷ 44 g/mol = 1 mole.

16. The mole ratio from the balanced equation 2Na + Cl₂ → 2NaCl is:
    a) 1:2
    b) 2:1
    c) 2:2
    d) 2:1:2

Answer: b) 2:1

Explanation: The mole ratio shows that 2 moles of sodium react with 1 mole of chlorine gas.

17. Which of the following compounds has the highest molar mass?
    a) H₂O
    b) CO₂
    c) NH₃
    d) C₆H₁₂O₆

Answer: d) C₆H₁₂O₆

Explanation: C₆H₁₂O₆ (glucose) has the highest molar mass compared to the others listed.

18. How many grams are in 3 moles of CaCl₂ (Molar mass = 110.98 g/mol)?
    a) 332.94 g
    b) 110.98 g
    c) 221.96 g
    d) 150 g

Answer: a) 332.94 g

Explanation: 3 moles × 110.98 g/mol = 332.94 g.

19. In a chemical reaction, if you have 2 moles of A and 3 moles of B, what is the mole ratio of A to B?
    a) 2:3
    b) 3:2
    c) 1:1.5
    d) 1.5:1

Answer: a) 2:3

Explanation: The ratio of the moles of A to B is directly taken from their coefficients.

20. If 5 moles of gas occupy a volume of 112 L at STP, what is the volume occupied by 1 mole?
    a) 22.4 L
    b) 56 L
    c) 28 L
    d) 44 L

Answer: a) 22.4 L

Explanation: At STP, 1 mole of an ideal gas occupies 22.4 L.