Final answer:
The non-polar functional group among the given options is the methyl group due to its symmetrical structure and even distribution of charge.
Step-by-step explanation:
The question asks which of the following functional groups is non-polar. Among the options provided, the non-polar functional group is the methyl group. A functional group's polarity is determined by the difference in electronegativity between the atoms involved and the symmetry of the molecule. To elaborate, hydroxyl, carboxyl, carbonyl, and phosphate groups are all considered polar because they contain electronegative atoms like oxygen (in hydroxyl, carboxyl, carbonyl) and both oxygen and phosphorus in phosphate, which create an uneven distribution of charge. The methyl group, in contrast, consists of a carbon atom bonded to three hydrogen atoms and is relatively symmetrical in its structure, resulting in an even distribution of charge hence it is non-polar. This is why, among the choices provided, 'c. Methyl' is the correct answer.