Chemistry MCQ Practice 16 — Science Foundation Course for Class 11 & 12

1. The van't Hoff factor for 0.1 M Al₂(SO₄)₃ solution (assuming complete dissociation) is:

(a) 2 (b) 3 (c) 5 (d) 8

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Correct Answer: (c) 5

Explanation:
Al₂(SO₄)₃ → 2Al³⁺ + 3SO₄²⁻ → total 5 ions

2. Which of the following is a ferromagnetic substance?

(a) Ni (b) Zn (c) Cu (d) Hg

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Correct Answer: (a) Ni

Explanation:
Nickel is ferromagnetic due to unpaired electrons

3. The coordination compound [Co(NH₃)₅Cl]Cl₂ shows which type of isomerism?

(a) Geometrical (b) Optical (c) Ionisation (d) Linkage

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Correct Answer: (c) Ionisation

Explanation:
Gives different ions in solution compared to its isomer

4. Which of the following is a reducing sugar?

(a) Sucrose (b) Maltose (c) Starch (d) Cellulose

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Correct Answer: (b) Maltose

Explanation:
Maltose has a free anomeric carbon (reducing end)

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

(a) 2-Chlorobutane (b) 1-Chlorobutane (c) 3-Chlorobutane (d) 2-Chloro-2-methylpropane

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Correct Answer: (a) 2-Chlorobutane

Explanation:
Secondary alkyl halide with four carbons

6. The correct order of acidic strength is:

(a) HF > HCl > HBr > HI (b) HI > HBr > HCl > HF (c) HCl > HBr > HI > HF (d) HF > HI > HBr > HCl

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Correct Answer: (b) HI > HBr > HCl > HF

Explanation:
Acidity increases down the group due to decreasing bond strength

7. The rate law for the reaction 2A + B → C is rate = k[A]²[B]. The order of reaction is:

(a) 2 (b) 3 (c) 1 (d) 0

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Correct Answer: (b) 3

Explanation:
Overall order = 2 + 1 = 3

8. The ore of aluminium is concentrated by:

(a) Froth flotation (b) Magnetic separation (c) Leaching (Bayer's process) (d) Distillation

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Correct Answer: (c) Leaching (Bayer's process)

Explanation:
Bauxite is purified by Bayer's process (leaching with NaOH)

9. The monomer of Teflon is:

(a) Vinyl chloride (b) Tetrafluoroethylene (c) Styrene (d) Acrylonitrile

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Correct Answer: (b) Tetrafluoroethylene

Explanation:
Teflon is polytetrafluoroethylene (PTFE)

10. The enzyme that converts glucose to ethyl alcohol is:

(a) Zymase (b) Invertase (c) Pepsin (d) Amylase

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Correct Answer: (a) Zymase

Explanation:
Zymase (from yeast) is used in alcoholic fermentation