An organic compound A having molecular formula C₆H₆O gives a violet colour with neutral FeCl₃ ​ solution. A on treatment with CO₂​ and NaOH at 400 K under pressure gives B which on acidification gives a compound C. The compound C reacts with acetyl chloride to give D which is popular pain killer. Deduce the structure of A, B, C and D.

What is the use of compound D?

as an analgesic

The correct answer is option 3. as an analgesic.

Aspirin (acetylsalicylic acid), identified as compound D in the sequence of reactions, is a well-known medication with multiple uses:

Analgesic (Pain Reliever): Aspirin is widely used to alleviate minor aches and pains, such as headaches, muscle pain, toothaches, and arthritis. It works by inhibiting the enzyme cyclooxygenase (COX), which reduces the production of prostaglandins, compounds that sensitize nerve endings to pain.

Antipyretic (Fever Reducer): Aspirin can reduce fever by acting on the hypothalamus, the part of the brain that regulates body temperature. It also inhibits the synthesis of prostaglandins, which play a role in the fever response.

Anti-inflammatory: Aspirin has anti-inflammatory properties, making it effective in reducing inflammation associated with conditions like rheumatoid arthritis and other inflammatory diseases.

Antiplatelet (Blood Thinner): Aspirin inhibits platelet aggregation, which helps prevent blood clots. This property is particularly useful in reducing the risk of heart attacks and strokes in individuals with cardiovascular diseases.

Given the options provided, the primary use of compound D (aspirin) is: as an analgesic.

However, it is important to note that aspirin also serves as an antipyretic and has additional uses in anti-inflammatory and antiplatelet therapy.