Q14 / 155 · WBJEE 2026 · Chemistry
Which of the following is the structure of pyrosulphuric acid?
- A
- B
- C
- Correct answerD
Solution
The chemical formula of pyrosulphuric acid (also known as oleum) is $H_2S_2O_7$.
In its structure, two sulphur atoms are linked together through an oxygen atom, forming a $S-O-S$ bridge. Each sulphur atom is further bonded to two oxygen atoms via double bonds and one hydroxyl ($-OH$) group via a single bond.
Let us analyze the given structures:
Option (A) represents peroxymonosulphuric acid ($H_2SO_5$), also known as Caro's acid, which contains a peroxy ($-O-O-$) linkage.
Option (B) represents peroxydisulphuric acid ($H_2S_2O_8$), also known as Marshall's acid, which contains a peroxy ($-O-O-$) linkage between two sulphur atoms.
Option (C) represents the hydrogen sulphate ion ($HSO_4^-$).
Option (D) represents pyrosulphuric acid ($H_2S_2O_7$), showing the correct $S-O-S$ linkage.
Answer:
In its structure, two sulphur atoms are linked together through an oxygen atom, forming a $S-O-S$ bridge. Each sulphur atom is further bonded to two oxygen atoms via double bonds and one hydroxyl ($-OH$) group via a single bond.
Let us analyze the given structures:
Option (A) represents peroxymonosulphuric acid ($H_2SO_5$), also known as Caro's acid, which contains a peroxy ($-O-O-$) linkage.
Option (B) represents peroxydisulphuric acid ($H_2S_2O_8$), also known as Marshall's acid, which contains a peroxy ($-O-O-$) linkage between two sulphur atoms.
Option (C) represents the hydrogen sulphate ion ($HSO_4^-$).
Option (D) represents pyrosulphuric acid ($H_2S_2O_7$), showing the correct $S-O-S$ linkage.
Answer:
Hence, the correct answer is option: 'D'.