Which of the following statements are correct? 

(i) All the three N—O bond lengths in HNO3 are equal. 

(ii) All P—Cl bond lengths in PCl₅ molecule in gaseous state are equal. 

(iii) P₄ molecule in white phosphorus have angular strain therefore white phosphorus is very reactive. 

(iv) PCl is ionic in solid state in which cation is tetrahedral and anion is octahedral.

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.