Which product is obtained by the dehydration of concentrated $H_2SO_4$ in the presence of $P_4O_{10}$?

Ozone $(O_3)$ belongs to which group of the periodic table?

Consider the following sulphur-based oxoacids: $H_2SO_3$,$H_2SO_4$,$H_2S_2O_8$,and $H_2S_2O_7$. Among these oxoacids,the number of those with a peroxo $(O-O)$ bond is $..........$

Which one of the following is most acidic?

Ozone is obtained from oxygen by:

The test of ozone $O_3$ can be done by