Chemistry - Biomolecules Question with Solution | TestHub
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Ketoses give Seliwanoff’s test faster than Aldoses.
Reason (R): Ketoses undergo -elimination followed by formation of furfural.
In the light of the above statements, choose the correct answer from the options given below:
Options:
Answer:
Solution:
Seliwanoff 's test is a differentiating test for Ketose and aldose. This test relies on the principle that the keto hexose are more rapidly dehydrated to form -hydroxy methyl furfural when heated in acidic medium which on condensation with resorcinol, Cherry red or brown red coloured complex is formed rapidly indicating a positive test.
Aldoses take longer time to produce colour because under the same conditions, aldoses form furfural slowly, probably because β-elimination is required before dehydration to furfural. Therefore prolonged heating should be avoided.
Hence, Assertion is true but Reason is false.