An oxyacid of sulphur contained $\mathrm{S}=\mathrm{S}$ linkage and the oxidation number of S in it is $+6$ and $-2$. It belongs to

For sulphur bonded to both oxygen and sulphur atoms,

x+(-1) +(-1) +(-2)+(-2)=0

x=+6

For sulphur bonded to only sulphur atom,

x+(-2)=0

x=+2

Thus, the given oxoacid is thiosulphuric acid.