Why does type of overlap given in the following figure not result in bond formation?

Explain the shape of BrF₅.

Structures of molecules of two compounds are given below :

(a) Which of the two compounds will have intermolecular hydrogen bonding and which compound is expected to show intramolecular hydrogen bonding.

(b) The melting point of a compound depends on, among other things, the extent of hydrogen bonding. On this basis explain which of the above two compounds will show higher melting point.

(c) Solubility of compounds in water depends on power to form hydrogen bonds with water. Which of the above compounds will form hydrogen bond with water easily and be more soluble in it.

Explain why PCl₅ is trigonal bipyramidal whereas IF₅ is square pyramidal.

In both water and dimethyl ether (CH₃ —Ο — CH₃ ), oxygen atom is central atom, and has the same hybridisation, yet they have different bond angles. Which one has greater bond angle? Give reason.