Mark the strongest acid.

Which of the following statements is not true for halogens?

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:

The halogen that is most easily reduced is

Acid strength of oxyacids of chlorine follows the order:

When chlorine gas is passed through an aqueous solution of a potassium halide in the presence of chloroform,a violet colouration is obtained. On passing more of chlorine water,the violet colour disappears and the solution becomes colourless. This test confirms the presence of ........... in the aqueous solution.