Which of the following substances is used to prepare $UF_6$ during the enrichment process of ${}_{92}U^{235}$?

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 $(i)$.

Which of the following represents the correct order of acidic nature?

Which of the following halogens is the most basic element?

Which two of the following salts are used for preparing iodized salt?
$(i) \, KIO_3$ $(ii) \, KI$
$(iii) \, I_2$ $(iv) \, HI$

$Silver \ nitrate$ $(AgNO_3)$ produces a black stain on the skin due to: