NEET2007ChemistryHydrocarbonsActual
Which of the following species participate in sulphonation of benzene ring ?
Options
- A( H ₂ SO ₄ )
- B( SO ₃ )
- C( HSO ₃⁻ )
- D( SO ₂⁻ )
Correct answer
B. ( SO ₃ )
Step-by-step solution
Most electrophilic substitution reactions are irreversible but sulphonation is an exception. Treatment of benzene with "oleum" (a solution of ( SO ₃ ) in conc. sulphuric acid) will give the sulphonic acid, the electrophile is sulphur trioxide ( ( SO ₃ ) ).