A) Water - Nitric acid
B) Benzene - Methanol
C) Water - Hydrochloric acid
D) Acetone - Chloroform
Correct Answer: B
Solution :
| Positive deviations are shown by such solutions in which solvent-solvent and solute-solute interactions are stronger than the solute-solvent interactions. In such solution, the interactions among molecule becomes weaker. Therefore their escaping tendency increases which results in the increase in their partial vapour pressures. |
| In pure methahol there exists intermolecular H-bonding. |
| \[--\underset{C{{H}_{3}}}{\mathop{\underset{|}{\mathop{O}}\,}}\,-H---\underset{C{{H}_{3}}}{\mathop{\underset{|}{\mathop{O}}\,}}\,-H---\underset{C{{H}_{3}}}{\mathop{\underset{|}{\mathop{O}}\,}}\,-H---\] |
| On adding benzene, its molecules come between ethanol molecules there by breaking H-bonds which weaken intermolecular forces. This result in increase in vapour pressure. |
You need to login to perform this action.
You will be redirected in
3 sec
