The ratio of sigma and $$\pi$$ bonds present in pyrophosphoric acid is ___________.

$$\mathrm{XeF}_{4}$$ reacts with $$\mathrm{SbF}_{5}$$ to form

$$[\mathrm{XeF}_{m}]^{\mathrm{n}+}\left[\mathrm{SbF}_{y}\right]^{z-}$$.

$$\mathrm{m}+\mathrm{n}+\mathrm{y}+\mathrm{z}=$$ __________

Sum of $$\pi$$-bonds present in peroxodisulphuric acid and pyrosulphuric acid is ___________

Consider the following sulphur based oxoacids.

$$\mathrm{H}_{2} \mathrm{SO}_{3}, \mathrm{H}_{2} \mathrm{SO}_{4}, \mathrm{H}_{2} \mathrm{S}_{2} \mathrm{O}_{8}$$ and $$\mathrm{H}_{2}\mathrm{S}_{2} \mathrm{O}_{7}$$.

Amongst these oxoacids, the number of those with peroxo $$(\mathrm{O}-\mathrm{O})$$ bond is ________.