Question

The oxoacid of sulphur which contains two sulphur atoms in different oxidation states is:

• A. pyrosulphurous acid
• B. hyposulphurous acid
• C. persulphuric acid
• D. pyrosulphuric acid

Answer 1

Answer: (A)

Disulphurous acid or pyrosulphurous acid is an oxoacid of sulphur with the formula $H_2{S}_2{O}_5$. The salts of disulphurous acid are called disulphites or metabisulphites. The oxidation state of the sulfur atom bonded to 3 oxygen atoms is +5 while the oxidation number of other sulfur atom is +3.