Question

Determine the correctness or otherwise of the following Assertion [a] and the Reason [r].
Assertion [a]: The difference in the respective melting points of butter and coconut oil is caused by the degrees of saturation of the corresponding fatty acid chain.
Reason [r]: Unsaturated fatty acid chains in fats/lipids become solid more easily because they are relatively straight and thus able to pack together more closely than saturated chains.

• A. Both [a] and [r] are true and [r] is the correct reason for [a]
• B. Both [a] and [r] are true but [r] is not the correct reason for [a]
• C. Both [a] and [r] are false
• D. [a] is true but [r] is false

Hint:

Unsaturated fatty acids have kinks in their structure due to double bonds, preventing them from packing closely, thus lowering the melting point.

Answer 1

The Correct Option is D

Step 1: Analyzing the assertion [a]. 
The assertion is correct. The melting points of butter (which contains more saturated fats) and coconut oil (which contains more unsaturated fats) differ due to the different levels of saturation in the fatty acid chains. Saturated fats have higher melting points compared to unsaturated fats. 
 

Step 2: Analyzing the reason [r]. 
The reason is incorrect. Unsaturated fatty acid chains have kinks due to double bonds, which prevent them from packing closely together, making the fat more likely to remain liquid at lower temperatures. Saturated fatty acids, on the other hand, pack tightly, leading to higher melting points. 
 

Step 3: Conclusion. 
The correct answer is (D) [a] is true but [r] is false