Answer 1

 Polar covalent compounds are good conductors of electricity because when these are dissolved in water, they ionize and act as electrolyte to produce ions which are responsible for conduction of electricity.
For example polar covalent compound HCl in water behaves as:
HCI + H₂O → H₃O⁺ + CI^-
These hydronium and chloride ions produced on dissolution of HCl in water are responsible for conduction of electricity.