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Chemistry MCQ Practice 14 — Science Foundation Course for Class 11 & 12
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1.
The number of atoms in 0.5 mole of glucose (C₆H₁₂O₆) is:
(a) 6.022 × 10²³
(b) 3.011 × 10²³
(c) 3.011 × 10²⁴
(d) 1.204 × 10²⁴
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Correct Answer: (c) 3.011 × 10²⁴
Explanation:
1 molecule glucose = 24 atoms → 0.5 mole = 0.5 × 24 × 6.022 × 10²³ = 3.011 × 10²⁴
2.
The oxidation state of sulphur in H₂S₂O₈ is:
(a) +6
(b) +7
(c) +5
(d) +4
Show Answer & Explanation
Correct Answer: (a) +6
Explanation:
Peroxodisulphuric acid has S in +6 state
3.
The pH of a buffer solution containing 0.1 M CH₃COOH and 0.1 M CH₃COONa is (Ka = 1.8×10⁻⁵):
(a) 4.74
(b) 7
(c) 5.0
(d) 3.74
Show Answer & Explanation
Correct Answer: (a) 4.74
Explanation:
pH = pKa + log([salt]/[acid]) = 4.74 + log(1) = 4.74
4.
The hybridisation of xenon in XeF₆ is:
(a) sp³d²
(b) sp³d³
(c) sp³d
(d) sp³
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Correct Answer: (b) sp³d³
Explanation:
Distorted octahedral geometry
5.
The IUPAC name of CH₃CH₂CH₂CH₂CH₂CH₂OH is:
(a) Hexanol
(b) Hexan-1-ol
(c) Pentan-1-ol
(d) Heptanol
Show Answer & Explanation
Correct Answer: (b) Hexan-1-ol
Explanation:
Six-carbon primary alcohol
6.
The number of sigma and pi bonds in CH₃-CH=CH-CH=CH₂ is:
(a) 11 sigma, 2 pi
(b) 10 sigma, 2 pi
(c) 12 sigma, 1 pi
(d) 9 sigma, 3 pi
Show Answer & Explanation
Correct Answer: (a) 11 sigma, 2 pi
Explanation:
1,3-Pentadiene has 11 σ and 2 π bonds
7.
The molarity of 5.85 g NaCl in 500 mL solution is:
(a) 0.2 M
(b) 0.1 M
(c) 0.5 M
(d) 1 M
Show Answer & Explanation
Correct Answer: (a) 0.2 M
Explanation:
Moles = 5.85 / 58.5 = 0.1, Volume = 0.5 L → M = 0.2
8.
The element with electronic configuration [Xe] 6s² 4f¹⁴ 5d¹⁰ 6p³ is:
(a) Bismuth
(b) Thallium
(c) Lead
(d) Polonium
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Correct Answer: (a) Bismuth
Explanation:
Atomic number 83 → Bismuth
9.
The functional group in isocyanides is:
(a) -NC
(b) -CN
(c) -NO₂
(d) -NH₂
Show Answer & Explanation
Correct Answer: (a) -NC
Explanation:
Isocyanide functional group is -N≡C
10.
The shape of XeOF₄ molecule is:
(a) Square pyramidal
(b) Octahedral
(c) Trigonal bipyramidal
(d) T-shaped
Show Answer & Explanation
Correct Answer: (a) Square pyramidal
Explanation:
5 bond pairs + 1 lone pair