Question
In which of the following, sulphur is present in + 5 oxidation state?
A.
Dithionic acid
B.
Sulphurous acid
C.
Sulphuric acid
D.
Disulphuric acid
Answer :
Dithionic acid
Solution :
$$\eqalign{
& \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,O.S.{\text{ of }}S \cr
& {\text{Dithionic acid}}\,{\text{ - }}\,{H_2}{S_2}{O_6}\,\,\,\,\,\, = + 5 \cr
& {\text{Sulphurous acid}}\,{\text{ - }}\,{H_2}S{O_3}\,\,\, = + 4 \cr
& {\text{Sulphuric acid}}\,{\text{ - }}\,{H_2}S{O_4}\,\,\,\,\,\,\, = + 6 \cr
& {\text{Disulphuric acid}}\,{\text{ - }}\,{H_2}{S_2}{O_7} = + 6 \cr} $$