Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason.
Assertion (A): A simple distillation can be used to separate a mixture of propanol and propanone.
Reason (R): Two liquids with a difference of more than 20°C in their boiling points can be separated by simple distillations.
In the light of the above statements, choose the most appropriate answer from the options given below:

First, we recall the working principle of simple distillation. Simple distillation is suitable for separating two miscible liquids if their boiling points differ appreciably. The empirical guideline taught in textbooks is that the boiling-point difference should be at least $$20^{\circ}\text{C}$$. If this condition is met, the vapour of the lower-boiling liquid becomes sufficiently richer in that component, condenses first, and a good separation is obtained without the need for a fractionating column.

Now we look at the two liquids mentioned in the Assertion.

We have propanone (commonly called acetone) with a boiling point of approximately $$56^{\circ}\text{C}$$, and we have propan-1-ol (commonly called 1-propanol) with a boiling point of approximately $$97^{\circ}\text{C}$$.

Let us calculate the difference in their boiling points:

$$\Delta T_{\text{b}} \;=\; 97^{\circ}\text{C} \;-\; 56^{\circ}\text{C} \;=\; 41^{\circ}\text{C}$$

We clearly see that $$\Delta T_{\text{b}} = 41^{\circ}\text{C} > 20^{\circ}\text{C}.$$

Because the boiling-point gap is more than the threshold of $$20^{\circ}\text{C},$$ the rule just recalled tells us that simple distillation will indeed be effective for this pair. Thus the statement “A simple distillation can be used to separate a mixture of propanol and propanone” is correct. Hence, Assertion (A) is true.

Next, we examine the Reason. The Reason states: “Two liquids with a difference of more than $$20^{\circ}\text{C}$$ in their boiling points can be separated by simple distillations.” This is exactly the same guideline we used above, so the Reason is also a correct scientific statement.

Furthermore, the Reason directly supplies the explanation for why simple distillation works in the specific case cited in the Assertion. We used that very rule—$$\Delta T_{\text{b}} > 20^{\circ}\text{C}$$—to justify the truth of (A). Therefore, (R) is not only true but also the correct explanation of (A).

Among the options, this correspondence matches Option B.

Hence, the correct answer is Option B.