JEE Main · 2020 · Shift-IImediumBIO-049

The correct observation in the following reactions is: Sucrose Hydrolysis A + B Seliwanoff's Reagent

Biomolecules · Class 12 · JEE Main Previous Year Question

Question

The correct observation in the following reactions is:

SucroseHydrolysisA+BSeliwanoff’s Reagent\text{Sucrose} \xrightarrow{\text{Hydrolysis}} \text{A} + \text{B} \xrightarrow{\text{Seliwanoff's Reagent}} \dots

Options
  1. a

    Gives no colour

  2. b

    Formation of red colour

  3. c

    Formation of violet colour

  4. d

    Formation of blue colour

Correct Answerb

Formation of red colour

Detailed Solution

Step 1: Sucrose Hydrolysis — Hydrolysis of sucrose yields a mixture of glucose (an aldose) and fructose (a ketose).

Step 2: Seliwanoff's Reagent Basis — This test distinguishes between aldoses and ketoses based on their rate of dehydration to furfural derivatives.

Step 3: Resulting Observation — Ketoses (like fructose) react much faster with resorcinol in acidic conditions to produce a cherry-red color. Hence, a red color is formed.

Remember: A positive Seliwanoff’s test\text{Seliwanoff's test} is specifically used to detect keto-sugars.

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