. The mixture that forms maximum boiling azeotrope is
A: Water + Nitric acid
B: Ethanol + Water
C: Acetone + Carbon disulphide
D: Heptane + Octane
Azeotropes or azeotropic mixtures are mixtures in which the constituent substances have same concentrations of vapour and fluid phases.
An azeotropic mixture has a constant or the same boiling points. The mixtures of vapours in such a case will also have the same composition as the liquid.
Azeotropic mixtures are of two types:
- Minimum boiling azeotropes
- Maximum boiling azeotropes
Azeotropic mixtures are classified on the basis of their deviation from the ideal boiling points or Roult’s law. An azeotrope showing negative deviation from the Roult’s law is a maximum boiling azeotrope and the one showing positive deviation is a minimum boiling azeotrope.
Out of the given options, only water + nitric acid show a negative deviation from the Roult’s law. This is because of the presence of stronger interactions between them as compared to solute-solute or solvent-solvent interactions.
Hence, the correct option is A: Water + Nitric acid.