Which of the following decreases down the halogen group?

$F_2$ is formed by reacting $K_2MnF_6$ with:

Which of the following fluorides can react with fluorine?

Which of the following properties does not correspond to the order $HI < HBr < HCl < HF$?

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R).$
Assertion $(A):$ $ICl$ is more reactive than $I_{2}.$
Reason $(R):$ $I-Cl$ bond is weaker than $I-I$ bond.
In the light of the above statements,choose the most appropriate answer from the options given below:

Deacon's process is used in the manufacture of