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Chemistry MCQ Practice 8 — Science Foundation Course for Class 11 & 12
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1.
The number of moles in 5.6 g of Fe (atomic mass 56) is:
(a) 0.1 mole
(b) 0.2 mole
(c) 1 mole
(d) 0.01 mole
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Correct Answer: (a) 0.1 mole
Explanation:
Moles = 5.6 / 56 = 0.1 mole
2.
The oxidation state of nitrogen in HNO₃ is:
(a) +3
(b) +5
(c) +1
(d) -3
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Correct Answer: (b) +5
Explanation:
+1 + x + 3(-2) = 0 → x = +5
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 formaldehyde (HCHO) is:
(a) sp
(b) sp²
(c) sp³
(d) sp³d
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Correct Answer: (b) sp²
Explanation:
Trigonal planar geometry around carbon
5.
The IUPAC name of CH₃CH₂CH₂CH₂CHO is:
(a) Pentanal
(b) Butanal
(c) Hexanal
(d) Propanal
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Correct Answer: (a) Pentanal
Explanation:
Five-carbon aldehyde
6.
The number of sigma bonds in CH₂=CH₂ is:
(a) 5 sigma, 1 pi
(b) 4 sigma, 2 pi
(c) 6 sigma, 0 pi
(d) 5 sigma, 2 pi
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Correct Answer: (a) 5 sigma, 1 pi
Explanation:
Ethene has 5 σ and 1 π bond
7.
The molarity of 4.9 g H₂SO₄ in 250 mL solution is:
(a) 0.2 M
(b) 0.1 M
(c) 0.4 M
(d) 1 M
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Correct Answer: (a) 0.2 M
Explanation:
Moles = 4.9 / 98 = 0.05, Volume = 0.25 L → M = 0.2
8.
The element with electronic configuration [Ar] 3d⁵ 4s¹ is:
(a) Cr
(b) Mn
(c) Fe
(d) Co
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Correct Answer: (a) Cr
Explanation:
Chromium (Z=24)
9.
The functional group in ethers is:
(a) -O-
(b) -OH
(c) -CO-
(d) -COO-
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Correct Answer: (a) -O-
Explanation:
Ether functional group is -O- between two alkyl groups
10.
The shape of IF₅ 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