Which one of the following noble gases is the least polarizable?

How are xenon fluorides $XeF_2$,$XeF_4$ and $XeF_6$ obtained?

The compound that cannot be formed by xenon is

The compound that cannot exist with xenon is

Which of the following statements regarding noble gases is incorrect?

$A$ xenon compound '$A$' upon partial hydrolysis gives $XeO_{2}F_{2}$. The number of lone pairs of electrons present in compound $A$ is ....... . (Round off to the nearest integer)