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

61. What is the number of grams in 0.1 moles of H₂SO₄ (Molar mass = 98 g/mol)?
    a) 9.8 g
    b) 10 g
    c) 20 g
    d) 15 g

Answer: a) 9.8 g

Explanation: 0.1 moles × 98 g/mol = 9.8 g.

62. In the reaction 2C₂H₄ + 5O₂ → 4CO₂ + 4H₂O, what is the mole ratio of ethylene to carbon dioxide?
    a) 1:2
    b) 1:4
    c) 2:4
    d) 5:4

Answer: b) 1:2

Explanation: The mole ratio is 2 moles of ethylene producing 4 moles of carbon dioxide, simplifying to 1:2.

63. How many moles are in 180 g of H₂O (Molar mass = 18 g/mol)?
    a) 6 moles
    b) 10 moles
    c) 5 moles
    d) 8 moles

Answer: a) 10 moles

Explanation: 180 g ÷ 18 g/mol = 10 moles.

64. In the equation 3Ca + 2Fe₂O₃ → 3CaO + 4Fe, what is the mole ratio of calcium to iron?
    a) 3:4
    b) 4:3
    c) 1:2
    d) 3:2

Answer: a) 3:4

Explanation: The ratio shows 3 moles of calcium produce 4 moles of iron.

65. If 2.5 moles of a substance have a mass of 100 g, what is its molar mass?
    a) 25 g/mol
    b) 40 g/mol
    c) 50 g/mol
    d) 20 g/mol

Answer: c) 40 g/mol

Explanation: Molar mass = mass/moles = 100 g / 2.5 moles = 40 g/mol.

66. What is the molar mass of calcium phosphate (Ca₃(PO₄)₂)?
    a) 310 g/mol
    b) 400 g/mol
    c) 215 g/mol
    d) 280 g/mol

Answer: a) 310 g/mol

Explanation: Molar mass = (3 × 40) + (2 × (31 + 4 × 16)) = 310 g/mol.

67. How many grams are in 1.5 moles of NaHCO₃ (Molar mass = 84 g/mol)?
    a) 126 g
    b) 112 g
    c) 150 g
    d) 100 g

Answer: a) 126 g

Explanation: 1.5 moles × 84 g/mol = 126 g.

68. In the reaction 2AgNO₃ + Cu → 2Ag + Cu(NO₃)₂, what is the mole ratio of silver nitrate to silver?
    a) 1:2
    b) 2:2
    c) 2:1
    d) 1:1

Answer: b) 1:1

Explanation: The coefficients indicate a 1:1 mole ratio between silver nitrate and silver.

69. In the reaction: 2H₂ + O₂ → 2H₂O, how many moles of water can be produced from 2 moles of oxygen?
    a) 2 moles
    b) 4 moles
    c) 3 moles
    d) 6 moles

Answer: b) 4 moles

Explanation: According to the reaction, 1 mole of O₂ produces 2 moles of H₂O, so 2 moles of O₂ produce 4 moles of H₂O.

70. What is the molar mass of iron(III) chloride (FeCl₃)?
    a) 130 g/mol
    b) 150 g/mol
    c) 165 g/mol
    d) 200 g/mol

Answer: c) 165 g/mol

Explanation: Molar mass = (55.85) + (3 × 35.45) = 165 g/mol.