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Chemistry MCQ Practice 9 — Science Foundation Course for Class 11 & 12
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1.
The number of moles in 5.85 g of NaCl is:
(a) 0.1 mole
(b) 0.5 mole
(c) 1 mole
(d) 0.01 mole
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Correct Answer: (a) 0.1 mole
Explanation:
Molar mass NaCl = 58.5 g/mol → 5.85 g = 0.1 mole
2.
The oxidation state of sulphur in Na₂S₂O₃ is:
(a) +2
(b) +4
(c) +6
(d) Average +2
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Correct Answer: (d) Average +2
Explanation:
2(+1) + 2x + 3(-2) = 0 → 2x = 4 → x = +2 (average)
3.
The pH of a solution with [H⁺] = 10⁻⁵ M is:
(a) 5
(b) 9
(c) 7
(d) 3
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Correct Answer: (a) 5
Explanation:
pH = -log(10⁻⁵) = 5
4.
The hybridisation of carbon in diamond is:
(a) sp
(b) sp²
(c) sp³
(d) sp³d
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Correct Answer: (c) sp³
Explanation:
Tetrahedral structure
5.
The IUPAC name of CH₃COCH₂CH₃ is:
(a) Butanone
(b) Butanal
(c) Pentanone
(d) Propanone
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Correct Answer: (a) Butanone
Explanation:
Four-carbon ketone
6.
The number of sigma and pi bonds in benzene is:
(a) 12 sigma, 3 pi
(b) 9 sigma, 6 pi
(c) 12 sigma, 6 pi
(d) 6 sigma, 6 pi
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Correct Answer: (a) 12 sigma, 3 pi
Explanation:
6 C-H + 6 C-C sigma, 3 pi bonds in resonance
7.
The normality of 0.25 M H₂SO₄ is:
(a) 0.25 N
(b) 0.5 N
(c) 1 N
(d) 0.125 N
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Correct Answer: (b) 0.5 N
Explanation:
Normality = 0.25 × 2 = 0.5 N
8.
The element with electronic configuration [Ar] 3d¹⁰ 4s¹ is:
(a) Cu
(b) Zn
(c) Ni
(d) Co
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Correct Answer: (a) Cu
Explanation:
Copper (Z=29)
9.
The functional group in nitriles is:
(a) -CN
(b) -NH₂
(c) -NO₂
(d) -CONH₂
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Correct Answer: (a) -CN
Explanation:
Cyano group (-C≡N)
10.
The shape of BrF₅ molecule is:
(a) Trigonal bipyramidal
(b) Square pyramidal
(c) Octahedral
(d) T-shaped
Show Answer & Explanation
Correct Answer: (b) Square pyramidal
Explanation:
5 bond pairs + 1 lone pair