Chapter 12: Basic concepts of organic reactions — Online MCQ Test
CHEMISTRY · CLASS 11th · Tamil Nadu State Board
Practice Chapter 12: Basic concepts of organic reactions with a free chapter-wise online MCQ test.
This chapter covers: Focusing on reaction mechanisms this chapter details covalent bond cleavage inductive electromeric resonance and hyperconjugation effects. Students examine electrophiles nucleophil....
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Chapter 12: Basic concepts of organic reactions — Important Questions & Answers
Which of the following species acts as an electrophile?
- A. NH3
- B. BF3
- C. H2O
- D. ROH
Answer: B. BF3
BF3 is an electron-deficient molecule with an incomplete octet, making it a Lewis acid or electrophile.
BF3 is an electron-deficient molecule with an incomplete octet, making it a Lewis acid or electrophile.
The permanent displacement of a shared pair of electrons in a carbon chain due to the difference in electronegativity is called:
- A. Electromeric effect
- B. Inductive effect
- C. Hyperconjugation
- D. Resonance
Answer: B. Inductive effect
Inductive effect is the permanent displacement of sigma electrons along a chain due to electronegativity differences.
Inductive effect is the permanent displacement of sigma electrons along a chain due to electronegativity differences.
Which effect is a temporary electronic effect?
- A. Inductive effect
- B. Resonance
- C. Electromeric effect
- D. Hyperconjugation
Answer: C. Electromeric effect
Electromeric effect operates only in the presence of an attacking reagent and vanishes when the reagent is removed.
Electromeric effect operates only in the presence of an attacking reagent and vanishes when the reagent is removed.
Which of the following pairs represents resonance structures?
- A. CH3-CH2-OH and CH3-O-CH3
- B. CH2=CH-CH=O and -CH2-CH=CH-O+
- C. CH3-COOH and CH3-COO-
- D. CH3-CH2-CH3 and CH3-CH2-CH2-CH3
Answer: B. CH2=CH-CH=O and -CH2-CH=CH-O+
Resonance structures involve the shift of pi or lone pair electrons without changing atomic positions.
Resonance structures involve the shift of pi or lone pair electrons without changing atomic positions.
In the reaction CH3-CH2-Br + OH- -> CH3-CH2-OH + Br-, the OH- ion acts as a:
- A. Electrophile
- B. Nucleophile
- C. Free radical
- D. Lewis acid
Answer: B. Nucleophile
The hydroxide ion donates an electron pair to the carbon atom, acting as a nucleophile.
The hydroxide ion donates an electron pair to the carbon atom, acting as a nucleophile.