Identify the correct order of increasing number of π−π- bonds in structures of the following molecules.I. H2S2O6II. H2SO3III. H2S2O5

To answer this question, we need to understand the structure of the given molecules and count the number of pi bonds in each.

I. H2S2O6 (Peroxodisulfuric acid): This molecule has two sulfur atoms, each bonded to four oxygen atoms. Two of these oxygen atoms are double bonded to the sulfur atom, resulting in two pi bonds per sulfur atom. Therefore, H2S2O6 has a total of 4 pi bonds.

II. H2SO3 (Sulfurous acid): This molecule has one sulfur atom bonded to three oxygen atoms. Two of these oxygen atoms are double bonded to the sulfur atom, resulting in two pi bonds. Therefore, H2SO3 has a total of 2 pi bonds.

III. H2S2O5 (Peroxomonosulfuric acid): This molecule has two sulfur atoms. One sulfur atom is double bonded to two oxygen atoms, resulting in two pi bonds. The other sulfur atom is double bonded to one oxygen atom, resulting in one pi bond. Therefore, H2S2O5 has a total of 3 pi bonds.

So, the correct order of increasing number of pi bonds is H2SO3 < H2S2O5 < H2S2O6.