Which of the following oxoacid of sulphur has -O-O- linkage?
- H2SO4, sulphuric acid
- H2S2O8, peroxodisulphuric acid
- H2S2O7, pyrosulphuric acid
- H2SO3, sulphurous acid
Answer
(2) H2S2O8, peroxodisulphuric acid
Solution
As per NCERT, peroxodisulphuric acid has the structure HO3S-O-O-SO3H, i.e. the two SO3H units are joined through a peroxide -O-O- linkage.
H2SO4 and H2SO3 contain only S–O / S=O and O–H bonds.
H2S2O7 contains an S–O–S linkage, not O–O.
Answer: (2)