HCl is a polar compound, Why HCl shows polar nature?

Assertion: CO_2 is non polar, while ROR is polar in nature. Reason: The dipole moments of two CO bonds are equal and opposite to each other in CO_2 , while in R-O-R molecules two dipoles of the R-O bonds are inclined to each other at an angle of 110°.

Why HF forms 'H' - bonding with ethyne even though it is non polar in nature?

What is the polar form of 1 - sqrt3i ?