Solved Practice Questions on Sulfonation, Nitration & Halogenation of Benzene | Organic Chemistry PDF Download

Q.1. In Cannizaro reaction, two molecules of aldehydes are reacted to produce _______
(a) Alcohol only
(b) Carboxylic acid only
(c) Alcohol and carboxylic acid
(d) Alcohol, carboxylic acid and ketone

Correct Answer is Option (c)
In Cannizaro reaction, two molecules of aldehydes are reacted to produce alcohol and carboxylic acid using a hydroxide base.

Q.2. HBr reacts fastest with ___________
(a) 2-methylpropan-2-ol
(b) Propan-1-ol
(c) Propan-2-ol
(d) 2-methylpropan-1-ol

Correct Answer is Option (a)
HBr reacts fastest with 2-methylpropan-2-ol. Hydrogen bromide is the diatomic molecule and a colorless compound. 

Q.3. The most stable carbonium ion is ___________
(a) Methyl carbonium ion
(b) 2° carbonium ion
(c) 1° carbonium ion
(d) 3° carbonium ion

Correct Answer is Option (d)
The most stable crbonium ion is 3⁰ carbonium ion. The least stable is primary or 1⁰ carbonium ion. 

Q.4. Which of the following is ortho-para directing group?
(a) –NHCOCH₃ 
(b) –NO₂ 
(c) –CN
(d) –CHO

Correct Answer is Option (a)
NHCOCH₃ is ortho-para directing group. NO, CN and CHO are meta-directing groups. 

Q.5. An activating substituent group activates ___________
(a) Ortho position
(b) Para position
(c) Both ortho and para positions
(d) Meta position

Correct Answer is Option (b)
An activating substituent group activates the ortho and para positions. It does not activate the meta position. 

Q.6. The compound that can be most readily sulphonated is ___________
(a) Benzene
(b) Nitrobenzene
(c) Toluene
(d) Chlorobenzene

Correct Answer is Option (c)
The compound that can be most readily sulphonated is toluene. Toulene contains CH₃ group. 

Q.7. Which of the following has the highest activation of the benzene ring?
(a) – NHCOCH₃ 
(b) –OH
(c) –NH₂ 
(d) –C₆H₅

Correct Answer is Option (c)
–NH₂ among the following has the highest activation of the benzene ring. In cases where the substituents are esters or amides, they are less activating because they form resonance structure that pull the electron density away from the ring. 

Q.8. Which of the following is a meta directing group?
(a) –NHCOCH₃
(b) –COOH
(c) –OH
(d) –OCH₃

Correct Answer is Option (b)
-COOH is a meta directing group. All the other options are ortho-para directing groups. 

Q.9. A deactivating substituent group directs ___________
(a) Ortho position
(b) Para position
(c) Both ortho and para positions
(d) Meta position

Correct Answer is Option (d)
A deactivating substituent group directs only meta position. It does not activate ortho or para positions.