What indicates a positive Acetaminophen Test?

A positive Acetaminophen Test is indicated by the appearance of a blue color after heating with hydrochloric acid. This reaction specifically identifies the presence of acetaminophen (also known as paracetamol) based on the formation of colored complexes under the given conditions.

The test involves heating the sample with hydrochloric acid, which leads to the formation of an intermediate compound that, when reacted further, produces a blue color. This signifies that acetaminophen is present in the sample being tested.

The other choices represent reactions or tests for different substances or are not relevant to the identification of acetaminophen. For instance, ferric chloride leading to a purple color is more associated with phenolic compounds in general rather than specifically indicating acetaminophen. Sodium hydroxide can produce various colors depending on other substances, and o-cresol may not yield a reliable result for acetaminophen, as its color response pertains to different chemical groups and not specifically to acetaminophen itself. Hence, the blue color produced after heating with hydrochloric acid is the definitive indication of the presence of acetaminophen.