Question

Which of the following is a non-polar molecule?

(a) Water

(b) Ammonia

(c) Ethylene

(d) Ethanol

The question was posed to me in exam.

The origin of the question is Biological Molecules Structures and Functions in portion Structures and Functions of Biological Molecules of Cell Biology

Answer 1

Right option is (c) Ethylene

Easiest explanation: Polar molecules occur when two atoms do not share electrons equally in a covalent bond. A dipole is formed, with part of the molecule carrying a slight positive charge and the other part carrying a slight negative charge. This happens when there is a difference between the electronegativity of each atom. An extreme difference forms an ionic bond, while a lesser difference forms a polar covalent bond. When molecules share electrons equally in a covalent bond there is no net electrical charge across the molecule. In a nonpolar covalent bond, the electrons are evenly distributed.