Theoretical yield is the quantity of a product obtained from the complete conversion of the limiting reactant in a chemical reaction. It is the amount of product resulting from a perfect chemical reaction and thus not the same as the amount you'll actually get from a reaction.
Four molecules have carbon as the central atom and hydrogen atoms around it. The shape that would give rise to a polar molecule is a bent shape. <span>The bent shape will not be symmetrical which will result to being polar. Hope this answers the question.</span>