The mixture that forms maximum boiling azeotrope is:(A) Water + Nitric acid(B) Ethanol + Water(C) Acetone + Carbon disulphide(D) Heptane + Octane

The correct answer is (B) Ethanol + Water.

An azeotrope is a mixture of liquids that boils at a constant temperature and has a constant composition. A maximum boiling azeotrope is a type of azeotrope where the boiling point of the mixture is higher than the boiling points of its individual components.

In the case of ethanol and water, they form a maximum boiling azeotrope at a composition of approximately 95.6% ethanol and 4.4% water by weight. This means that when this mixture is heated, it will boil at a constant temperature, and the vapor produced will have the same composition as the liquid mixture.

In the other options:
(A) Water + Nitric acid: Water and nitric acid do not form a maximum boiling azeotrope.
(C) Acetone + Carbon disulphide: Acetone and carbon disulfide do not form a maximum boiling azeotrope.
(D) Heptane + Octane: Heptane and octane do not form a maximum boiling azeotrope.

Therefore, the correct answer is (B) Ethanol + Water.