Question

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 β-elimination followed by formation of furfural. 

In the light of the above statements, choose the correct answer from the options given below : 

(1) (A) is false but (R) is true 

(2) Both (A) and (R) are true and (R) is the correct explanation of (A) 

(3) (A) is true but (R) is false 

(4) Both (A) and (R) are true but (R) is not the correct explanation of (A)

Answer 1

(3) (A) is true but (R) is false 

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 5-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.