Oxyacids of chlorine show similarity in

Consider the following statements about the oxides of halogens:
$A$. At room temperature,$OF_2$ is thermally stable.
$B$. Order of stability of oxides of halogens is $I > Br > Cl$.
$C$. $I_2O_5$ is used in the estimation of $CO$.
$D$. $ClO_2$ is used as a bleaching agent.
The correct statements are:

Anhydrous ferric chloride is prepared by

Give reason to explain why $ClF_3$ exists but $FCl_3$ does not exist.

Which of the following interhalogen compounds does not exist?

Bromine is obtained on a commercial scale from