Question

Write the molecular and structural formulae of: Dithionous acid.

Answer 1

Hint: Dithionous acid is a sulfur oxoacid with chemical formula ${H_2}{S_2}{O_4}$. It is unstable in pure form, but its salts known as dithionite, are stable. It is also known as hypodisulphurous acid. It is a conjugate acid of a dithionite.

Complete step by step answer:
The oxoacids of sulphurs are numerous and quite important. Many of the oxoacids of sulphur do not exist as free acids, but are known as anions and salts. Acids ending with –ous have S in the oxidation state (+4) and form salts ending with –ite. Acids ending in-ic have S in the oxidation state(+4) and form salts ending in –ate.
The oxoanions have strong pi-bonds and so they have little tendency to polymerize compared with phosphates and silicates. In the question we are asked about dithionous acid one of the oxoanions of sulphur therefore its molecular structure and structural formulae is:
Molecular structure: ${H_2}{S_2}{O_4}$
Structural formulae:
 

Additional information: Dithionous acid, also known as dithionige saeure or ${H_2}{S_2}{O_4}$ , belongs to the class of inorganic compounds known as non-metal dithionite. These are inorganic non-metallic compounds containing a dithionite as its largest oxoanion. Sodium dithionite is a white powder used as a reductant and a bleaching agent. It is also used to reduce the nitro group to an amino group in organic reactions.

Note:
Be careful while drawing the structure to dithionous acid the oxidation state of sulphur is (+3) in this particular oxoanion of sulphur.