The azeotropic mixture of water and ethonal boils at 78.15°C. When this mixture is distilled, it is possible to obtain:

Neither H₂O nor C₂H₅OH in their pure state

The correct answer is option 4. Neither H₂O nor C₂H₅OH in their pure state.

An azeotropic mixture is a liquid mixture of two or more components that boils at a constant temperature, forming a vapor with the same composition as the liquid. In the case of the azeotropic mixture of water and ethanol, it boils at 78.15°C, which is lower than the boiling points of pure water (100°C) and pure ethanol (78.37°C).

During distillation, when the azeotropic mixture is heated and the vapor is collected, the composition of the vapor remains the same as the liquid. Therefore, it is not possible to obtain pure water (H₂O) or pure ethanol (C₂H₅OH) by distilling the azeotropic mixture. The vapor collected during distillation will still contain both water and ethanol in the same proportion as the azeotropic mixture.

To separate water and ethanol into their pure states, additional techniques such as azeotropic distillation with an entrainer or other separation methods like molecular sieves or rectification columns are required. These methods exploit differences in boiling points or other properties to achieve separation.

Therefore, option (4) is the correct answer: Neither H₂O nor C₂H₅OH can be obtained in their pure states by distilling the azeotropic mixture of water and ethanol.