Chemistry MCQ Practice 29 — Science Foundation Course for Class 11 & 12

1. A solution of urea (molar mass 60) is prepared by dissolving 6 g in 100 g of water. The molality of the solution is:

(a) 1 m (b) 0.5 m (c) 2 m (d) 0.1 m

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Correct Answer: (a) 1 m

Explanation:
Molality = (6/60) / 0.1 = 1 m

2. The crystal field splitting parameter (Δ₀) is maximum for:

(a) [CoF₆]³⁻ (b) [Co(H₂O)₆]²⁺ (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

3. Which of the following is a cross-linked polymer?

(a) Polythene (b) Bakelite (c) Nylon-6,6 (d) PVC

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Correct Answer: (b) Bakelite

Explanation:
Bakelite is a cross-linked thermosetting polymer

4. The vitamin required for the absorption of calcium is:

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

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Correct Answer: (b) Vitamin D

Explanation:
Vitamin D helps in calcium and phosphorus absorption

5. The IUPAC name of CH₃-CH₂-C(CH₃)₂-CH₂-CH₃ is:

(a) 3,3-Dimethylpentane (b) 2,2-Dimethylpentane (c) 3-Methylhexane (d) 2-Methylhexane

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Correct Answer: (a) 3,3-Dimethylpentane

Explanation:
Longest chain of 5 carbons with two methyl groups at position 3

6. The correct order of acidic strength of carboxylic acids is:

(a) HCOOH > CH₃COOH > C₂H₅COOH (b) CH₃COOH > HCOOH > C₂H₅COOH (c) C₂H₅COOH > CH₃COOH > HCOOH (d) CH₃COOH > C₂H₅COOH > HCOOH

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Correct Answer: (a) HCOOH > CH₃COOH > C₂H₅COOH

Explanation:
+I effect of alkyl group decreases acidity

7. The time taken for 50% completion of a second order reaction is:

(a) 1 / (k [A]₀) (b) 0.693 / k (c) 2.303 / k (d) Independent of concentration

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Correct Answer: (a) 1 / (k [A]₀)

Explanation:
t₁/₂ = 1 / (k [A]₀) for second order reaction

8. The process used for concentration of bauxite ore is:

(a) Froth flotation (b) Magnetic separation (c) Leaching with NaOH (d) Distillation

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Correct Answer: (c) Leaching with NaOH

Explanation:
Bayer's process (leaching of bauxite)

9. The polymer used in making artificial blood vessels is:

(a) Silicone (b) Polyurethane (c) Teflon (d) Nylon

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Correct Answer: (b) Polyurethane

Explanation:
Polyurethane is biocompatible and used in medical implants

10. The enzyme that converts proteins to amino acids is:

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

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Correct Answer: (b) Trypsin

Explanation:
Trypsin is a proteolytic enzyme in the small intestine