Chemistry MCQs – Set 6

🔬 Chemistry MCQs (Set–6)

51. The number of moles in 44 g of CO₂ is:
A) 0.5
B) 1
C) 2
D) 44
👉 Answer: B) 1
(Molar mass of CO₂ = 44 g/mol)

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52. The value of Avogadro’s number is:
A) 6.022 × 10²³
B) 3.011 × 10²³
C) 1.66 × 10⁻²⁷
D) 22.4
👉 Answer: A) 6.022 × 10²³

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53. Which of the following orbitals has the highest energy in a hydrogen atom?
A) 1s
B) 2s
C) 2p
D) 3s
👉 Answer: D) 3s

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54. The rate of reaction increases with increase in temperature because:
A) Activation energy decreases
B) More molecules have energy greater than activation energy
C) Collisions decrease
D) Concentration increases
👉 Answer: B) More molecules have energy greater than activation energy

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55. The oxidation number of Mn in KMnO₄ is:
A) +2
B) +4
C) +6
D) +7
👉 Answer: D) +7

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56. Which of the following is the strongest reducing agent?
A) Na
B) Mg
C) Al
D) Zn
👉 Answer: A) Na

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57. The unit of rate constant for a first-order reaction is:
A) mol L⁻¹ s⁻¹
B) s⁻¹
C) L mol⁻¹ s⁻¹
D) mol⁻¹ L s⁻¹
👉 Answer: B) s⁻¹

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58. Which of the following shows hydrogen bonding?
A) CH₄
B) NH₃
C) CO₂
D) HCl
👉 Answer: B) NH₃

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59. The equivalent weight of H₂SO₄ in acid-base reaction is:
A) 98
B) 49
C) 32
D) 18
👉 Answer: B) 49

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60. The coordination number of cobalt in [Co(NH₃)₆]³⁺ is:
A) 3
B) 4
C) 5
D) 6
👉 Answer: D) 6