Which of the following is incorrectly matched?

Fluorine reacts with water to produce

An aqueous solution of a halogen salt of potassium reacts with the same halogen $X_2$ to give $KX_3$,a brown-coloured solution,in which the halogen exists as the $X_3^-$ ion,$X_2$ acts as a Lewis acid,and $X^-$ acts as a Lewis base. The halogen $X$ is:

Which of the following represents the correct order of oxidising power of halogens in water?

$PbF_4$ and $PbCl_4$ exist,while $PbBr_4$ and $PbI_4$ do not. The reason for this is .......

$A$ greenish yellow gas reacts with an alkali metal hydroxide to form a halate which can be preferentially used in fire works and safety matches,the gas and halate respectively are