ANS:A - acetone chloroform

The system with the maximum boiling azeotrope at 1 atm pressure is ethyl alcohol-water. An azeotrope is a mixture of liquids that maintains a constant boiling point and composition throughout distillation, which means that the vapor has the same composition as the liquid. In the case of the ethyl alcohol-water system, at a specific composition (approximately 95.6% by weight of ethyl alcohol and 4.4% by weight of water), the mixture forms a maximum boiling azeotrope at atmospheric pressure. This means that this particular mixture has a boiling point lower than that of either pure component, and it cannot be further separated by simple distillation. Therefore, among the options provided, the ethyl alcohol-water system has the maximum boiling azeotrope at 1 atm pressure.