Which one of the following is not correct ?

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For an ideal solution ΔH_mix = 0;ΔV_mix = 0

A mixture of phenol and aniline shows negative deviation in its vapour pressure

A mixture of carbondisulphide and acetone shows positive deviation in its vapour pressure

Nitric acid and water mixture shows large positive deviation in its vapour pressure and forms minimum boiling point azeotrope

answer is D.

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Detailed Solution

(1) An ideal solution is the one in which ,A - B interactions are equal to that of A - A and B - B interaction.

No new attractions (or) repulsions are developed between A and B.

No heat is released (or) absorbed,

No expansion(or) contraction ,

But due to mixing of A & B (whether ideal or non ideal), randomness always increases,

formation of an ideal or non ideal solution is always spontaneous,

(2) H-bonding between the molecules of phenol and aniline is stronger than H-bonding in phenol & in Aniline

Thus phenol - aniline azeotrope shows negative deviation

(3) The dipole- dipole attractions in acetone are disturbed by the addition of non-polar CS₂ molecules.

Thus acetone-CS₂ azeotrope shows positive deviation

(4) Mineral acids (like HNO₃) when dissolved in water produces ions , ion-dipole attractions develop.

HNO₃- water ( ion-dipole ) attractions are stronger than HNO₃- HNO₃(H-bonding) and H₂O - H₂O (H-bonding)

The VP of the mixture is lesser than expected from Raoult's law, It shows negative deviation

Hence it is a maximum boiling azeotrope

( BP of azeotrope will be higher than any one of the component)

4^th option is false

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