Selected MCQ

Current Question
Aromaticity requires a cyclic, planar, conjugated system containing:
  • A. (4n) (\pi) electrons
  • B. (2n) (\sigma) electrons
  • C. (4n+2) (\pi) electrons
  • D. Any even number of (\pi) electrons
Correct Answer: C
Explanation:
Hückel’s rule specifies (4n+2) delocalized (\pi) electrons for aromatic stabilization.
Related Question 1
Which compound has trigonal planar geometry?
  • A. NH₃
  • B. CH₄
  • C. BF₃
  • D. H₂O
Correct Answer: C
Explanation:
BF₃ is sp² hybridized.
Related Question 2
A system with negative heat capacity is characteristic of:
  • A. Ideal gas
  • B. Black holes and self-gravitating systems
  • C. Solids
  • D. Liquids
Correct Answer: B
Explanation:
Adding energy can decrease temperature in gravitational systems.
Related Question 3
Which system controls reflex?
  • A. Digestive
  • B. Nervous
  • C. Respiratory
  • D. Circulatory
Correct Answer: B
Explanation:
Nervous system handles reflexes.
Related Question 4
Which system removes waste?
  • A. Digestive
  • B. Excretory
  • C. Respiratory
  • D. Circulatory
Correct Answer: B
Explanation:
Kidneys filter waste.
Related Question 5
Which system exchanges gases?
  • A. Digestive
  • B. Respiratory
  • C. Circulatory
  • D. Nervous
Correct Answer: B
Explanation:
Lungs exchange gases.