The solution which shows positive deviation from Raoult's law, is the mixture of

Ethanol and acetone

The correct answer is option 2. Ethanol and acetone.

Raoult's Law describes the ideal behavior of solutions where the partial pressure of a component in a mixture is directly proportional to its mole fraction. However, some real solutions deviate from this ideal behavior.

Positive deviation from Raoult's Law occurs when the intermolecular interactions between the components of the mixture are weaker than the interactions between the pure components themselves. This leads to a higher vapor pressure for the mixture than predicted by Raoult's Law.

Analysis of options:

1. Nitric acid and water: These components can form hydrogen bonds, which are relatively strong intermolecular interactions. So, a deviation is unlikely.

2. Ethanol and acetone: These are polar molecules, but the intermolecular forces between them (hydrogen bonding and dipole-dipole interactions) might be weaker than the hydrogen bonding within pure ethanol or pure acetone. This can lead to a positive deviation.

3. Phenol and Aniline: Both can form hydrogen bonds, and interactions between them might be comparable to those within pure components. So, a positive deviation is less likely.

4. Chloroform and Acetone: These are polar molecules with dipole-dipole interactions, but the interactions between them might not be as strong as the interactions within pure chloroform or pure acetone. This could lead to a positive deviation.

Among the given options, ethanol and acetone have the most potential for a positive deviation due to the possibility of weaker intermolecular interactions between them compared to the interactions within their pure forms. It's important to note that the extent of deviation can vary depending on the specific composition of the mixture.