Chemistry MCQ Practice 24 — Science Foundation Course for Class 11 & 12

1. The colligative property that is used to determine the molecular mass of proteins is:

(a) Relative lowering of vapour pressure (b) Elevation in boiling point (c) Osmotic pressure (d) Depression in freezing point

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Correct Answer: (c) Osmotic pressure

Explanation:
Osmotic pressure is measurable at room temperature and suitable for macromolecules

2. The crystal field splitting energy (Δ₀) is highest for:

(a) [CoF₆]³⁻ (b) [Co(H₂O)₆]³⁺ (c) [Co(NH₃)₆]³⁺ (d) [Co(CN)₆]³⁻

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Correct Answer: (d) [Co(CN)₆]³⁻

Explanation:
CN⁻ is the strongest field ligand among the given options

3. Which of the following is a biodegradable polymer?

(a) Polythene (b) PVC (c) PHBV (d) Teflon

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Correct Answer: (c) PHBV

Explanation:
Poly-β-hydroxybutyrate-co-β-hydroxyvalerate is biodegradable

4. The vitamin required for vision is:

(a) Vitamin A (b) Vitamin B₁₂ (c) Vitamin C (d) Vitamin D

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Correct Answer: (a) Vitamin A

Explanation:
Retinol is essential for formation of rhodopsin

5. The IUPAC name of the compound CH₃-CH₂-CH(Cl)-CH₂-CH₃ is:

(a) 3-Chloropentane (b) 2-Chloropentane (c) 1-Chloropentane (d) 2-Methyl-3-chlorobutane

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Correct Answer: (a) 3-Chloropentane

Explanation:
Longest chain with lowest number to substituent

6. The correct order of boiling points of the following is:

(a) n-Butane > 2-Methylpropane > n-Pentane (b) n-Pentane > n-Butane > 2-Methylpropane (c) 2-Methylpropane > n-Butane > n-Pentane (d) All have same boiling point

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Correct Answer: (b) n-Pentane > n-Butane > 2-Methylpropane

Explanation:
Boiling point increases with molecular weight and surface area

7. For a first order reaction, the time required for 99% completion is:

(a) 2 t₁/₂ (b) 6.64 t₁/₂ (c) 4 t₁/₂ (d) 10 t₁/₂

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Correct Answer: (b) 6.64 t₁/₂

Explanation:
t = (2.303/k) log(100/1) ≈ 6.64 t₁/₂

8. The metal that is refined by van Arkel method is:

(a) Nickel (b) Titanium (c) Copper (d) Zinc

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Correct Answer: (b) Titanium

Explanation:
Van Arkel process uses volatile TiI₄ for purification of Ti and Zr

9. The polymer used in making bullet-proof glass is:

(a) Perspex (b) Polycarbonate (c) Bakelite (d) Nylon

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Correct Answer: (b) Polycarbonate

Explanation:
Lexan (polycarbonate) is used for bullet-proof glass

10. The enzyme that converts starch into maltose is:

(a) Amylase (b) Maltase (c) Pepsin (d) Lipase

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Correct Answer: (a) Amylase

Explanation:
Salivary and pancreatic amylase hydrolyse starch to maltose