What is meant polarity?

Answer 1

I have been through many chemistry classes before and have never come across this exact phrase, but I think I may know what you mean.

Certain atoms draw electrons more strongly than others, for a wide variety of reasons. Therefore in some molecules, electrons are more likely to be found in one area of the molecule than in another. For example, fluorine attracts electrons very strongly and carbon and hydrogen do not. Therefore in a molecule such as CH3F the electrons would be drawn more closely to the fluorine in the molecule than the carbon. This gives the fluorine end of the molecule a permanent negative charge and the carbon a permanent positive charge (and thusly the polarity is intrinsic to the molecules structure).

This is opposed to other molecules in which polarity is transient (inconsistently present) because none of the atoms draw on the electrons more strongly than the other atoms. In a molecule of ethane (C2H6) neither carbon draws electrons more strongly. You can, however, get polarity if by chance more of the electrons travel to one side of the molecule (remember that electrons obey quantum mechanics and can appear anywhere in a given cloud) and create a temporary negative charge. Therefore polarity can be present, but it isn't intrinsic (the polarity had nothing to do with the electronegativities of the atoms).

Sorry if I misinterpreted the question.