JEE PYQ: Biomolecules And Polymers Question 19
Question 19 - 2020 (02 Sep Shift 2)
The correct observation in the following reactions is:
Sucrose $\xrightarrow{\text{Glycosidic bond cleavage (Hydrolysis)}}$ A + B $\xrightarrow{\text{Seliwanoff’s reagent}}$ ?
(1) Formation of blue colour
(2) Gives no colour
(3) Formation of red colour
(4) Formation of violet colour
Show Answer
Answer: (3)
Solution
Seliwanoff reagent $\to$ [Resorcinol + Conc. HCl]. It is used to distinguish aldoses and ketoses. Ketoses show red colour whereas aldoses show light pink colour with Seliwanoff Reagent. Hydrolysis of sucrose gives glucose and fructose. Fructose (a ketose) gives red colour.
BETA
