Which of the following statements are true? 

(i) Only type of interactions between particles of noble gases are due to weak dispersion forces. 

(ii) Ionisation enthalpy of molecular oxygen is very close to that of xenon. 

(iii) Hydrolysis of XeF₆ is a redox reaction. 

(iv) Xenon fluorides are not reactive.

HClO₄ is the most acidic compound.

Group number = 11 (Atomic number = 111)

Heavier element of p block do not from pπ− pπ bonds as their atomic orbital are so large and diffius that they cannot have effecitve overlapping.

The inertness of ? subshell electrons towards bond formation is known as inert pair effect. This effect increases down the group thus, for Sn,  oxidation state is more stable, whereas, for Pb,  oxidation state is more stable, i.e.,  is reducing while  is oxidising.