Question

Which among the following combinations is maximum boiling azeotrope?
A.${H_2}O + C{H_3}OH$
B.$CC{l_4} + CHC{l_3}$
C.${\left( {C{H_3}} \right)_2}CO + {C_2}{H_5}OH$
D.${H_2}O + HN{O_3}$

Answer 1

Hint: We have to know that the solutions that boil at constant temperature such as pure liquid and have the same composition both in liquid and vapour state are called azeotropes. The substances of azeotropes could not be extracted by fractional distillation. Azeotropes are formed by non-ideal solutions only.

Complete step by step solution:
We have to remember that the positive deviation from Raoult’s law is seen when the observed vapor pressure is more than expected vapor pressure and it takes place when the A-B attractions are weaker than the average of the intermolecular attractions in the pure constituents of the mixture.
As we know that the negative deviation from Raoult’s law takes place when the intermolecular forces between the different molecules are stronger than the average of the intermolecular forces in the pure substances.
We have to remember that solutions which show negative deviation from maximum boiling azeotrope and solutions that show positive deviation from minimum boiling azeotrope. The boiling point of an azeotrope is not equal to the boiling points of any of the constituents of the azeotrope.
Maximum-boiling azeotrope is known to be a negative azeotrope as the vapour pressure of the solution is lower than as predictable vapor pressure by Raoult's law. It boils at a higher temperature than the pure constituents.
In the given options, a mixture of water and nitric acid would show negative deviation from ideality because of the presence of hydrogen bonding between the molecules.
Therefore, the option (D) is correct.

Note:We have to know an ideal solution follows Raoult's law at all pressures and temperatures. The solute-solute and the solvent-solvent interactions are almost similar to solute-solvent interactions. No association or dissociation takes place. It does not give azeotrope mixture. When the intermolecular forces of attractions are identical or equal, we observe an ideal solution.