NEETChemistryGeneral Organic Chemistry
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): During steam distillation, the organic liquid boils at a temperature lower than its normal boiling point. Reason (R): The organic liquid boils when the sum of its vapour pressure and the vapour pressure of water becomes equal to the atmospheric pressure. In the light of the above statements, choose
Options
- ABoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A)
- BAssertion (A) is true but Reason (R) is false
- CBoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)
- DAssertion (A) is false but Reason (R) is true
Correct answer
C. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)
Step-by-step solution
In steam distillation, a mixture of steam and the volatile organic compound is vaporised. The mixture boils when the sum of the vapour pressures of the organic liquid ( p₁ ) and water ( p₂ ) becomes equal to the atmospheric pressure ( p ), i.e., p = p₁ + p₂ . Since the partial vapour pressure of the organic liquid ( p₁ ) is less than the total atmospheric pressure ( p ), the organic liquid reaches its required partial pressure at a lower temperature than its normal boiling point. Consequently, it vaporises at a low