Question

Benzenesulfonic acid is prepared from the:
(A) hydrolysis of benzene
(B) neutralization of benzene
(C) sulfonation of benzene
(D) both A and B

Answer 1

Hint : The organosulfur compound benzenesulfonic acid (conjugate base benzenesulfonate) has the formula $C_6H_6O_3S$. It is the most basic aromatic sulfonic acid. It forms white waxy solids or deliquescent sheet crystals that are soluble in water, ethanol, and benzene but insoluble in nonpolar solvents like diethyl ether. It is often stored in the form of alkali metal salts. It has a very acidic aqueous solution.

Complete Step By Step Answer:
Benzenesulfonic acid is made by sulfonating benzene with concentrated sulfuric acid as follows:
Sulfonation is a reversible reaction that produces benzenesulfonic acid by adding sulfur trioxide and fuming sulfuric acid. A concentrated solution of dissolved sulphur trioxide in sulfuric acid is known as fuming sulfuric acid, or oleum. Because oxygen is very electronegative, the oxygens in sulphur trioxide pull electrons away from it, making the sulphur electrophilic. To make benzenesulfonic acid, benzene attacks sulphur (and subsequent proton transfers occur). The reaction is reversed by adding hot aqueous acid to benzenesulfonic acid to produce benzene. Aromatic sulfonation, also known as "one of the most important reactions in industrial organic chemistry," is demonstrated in this conversion. Sulfonic acids are commonly used as a protecting group or as a meta director in electrophilic aromatic substitution.
When heated in water near $200 ^oC$ benzenesulfonic acid sulfonate. The temperature of sulfonation correlates with the ease of the sulfonation.
Hence, Option (C) is correct.

Note :
Surfactants in laundry detergent include benzenesulfonic acid salts such as Sodium benzenesulfonate (Ludigol) and Monoethanolamine benzenesulfonate. Besilates or besylates are benzene sulfonate salts that are used to make a variety of pharmaceutical drugs.