Which of the following compounds is $NOT$ in the gaseous phase at $25^{\circ} C$?

Identify the incorrect statement about the interhalogen compounds.

Which of the following oxoacids of chlorine is the least oxidizing in nature?

Which of the following is a correct statement?

The correct statement$(s)$ regarding $(i) HClO$,$(ii) HClO_2$,$(iii) HClO_3$,and $(iv) HClO_4$ is(are):
$(A)$ The number of $Cl=O$ bonds in $(ii)$ and $(iii)$ together is two.
$(B)$ The number of lone pairs of electrons on $Cl$ in $(ii)$ and $(iii)$ together is three.
$(C)$ The hybridization of $Cl$ in $(iv)$ is $sp^3$.
$(D)$ Amongst $(i)$ to $(iv)$,the strongest acid is $(i)$.

Discuss variations in atomic radii and ionization enthalpies in halogens.