Identify the correct decreasing order of bond dissociation enthalpy from the following.

The element that does not show a variable oxidation state is:

The colour of the $X_2$ molecules of group $17$ elements changes gradually from yellow to violet down the group. This is due to
[$A$] the physical state of $X_2$ at room temperature changes from gas to solid down the group
[$B$] decrease in $HOMO-LUMO$ gap down the group
[$C$] decrease in $\pi^*-\sigma^*$ gap down the group
[$D$] decrease in ionization energy down the group

Iodine is not oxidized to iodic acid $(HIO_3)$ by which of the following?

The interhalogen compound formed from the reaction of bromine with an excess of fluorine is:

Which of the following oxidizes $H_2O$ to oxygen?