Question

Compound $ {{\text{S}}_{\text{2}}}{{\text{O}}_{\text{8}}} $ have:
(A) $ {\text{S - S}} $ bond
(B) $ {\text{S - O}} $ bridge
(C) $ {\text{O - O}} $ bridge
(D) None of the above

Answer 1

Hint: To answer this question, you must recall the structure of the given chemical species. First we draw the chemical structure of the compound and then see which of the following given conditions is satisfied in its structure.

Complete step by step solution
 $ {{\text{S}}_{\text{2}}}{{\text{O}}_{\text{8}}} $ is an ionic species and carries a charge of $ - 2 $ . It is known as the peroxy disulfate ion. It is an oxyanion of sulphur and the conjugate base of the peroxydisulfuric acid. The ion is commonly known as persulfate ion or as peroxo disulphate anions. Another similar species is peroxo- monosulphate ion which similarly is the conjugate base of the peroxy mono sulphuric acid.
The structure of $ {{\text{S}}_{\text{2}}}{{\text{O}}_{\text{8}}} $ can be imagined as two sulphate groups joined together. Each sulphur is bonded to four carbon atoms, doubly bonded to two and single bonds are formed with the other two. The two terminal oxygen atoms satisfy their valency by carrying a negative charge which accounts for the -2 charge on the species. The inner oxygen atoms are bonded to each other and form a bridging oxygen- oxygen bond between the two sulphur atoms. The structure can be drawn as:

The correct answer is C.

Note
We can see the peroxodisulphate ions as the combination of two sulphate groups. We know that a peroxy bond breaks readily forming free radicals. Due to this property, salts of peroxodisulphate ions are used for the polymerization of many alkenes namely styrene, acrylonitrile, and fluoroalkenes. The oxygen- oxygen bond cleaves homolytically. It is also used for the treatment of wastewater.