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JEE Main · 2022 · 25 Jul 2022 · Shift 1 · Alcohols Phenols and Ethers

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Given below are two statements:

Statement I: On heating with KHSO₄, glycerol is dehydrated and acrolein is formed.

Statement II: Acrolein has fruity odour and can be used to test glycerol's presence.

Choose the correct option.
  1. (A)Both Statement I and Statement II are correct.
  2. (B)Both Statement I and Statement II are incorrect
  3. (C)Statement I is correct but Statement II is incorrect.✓ Correct
  4. (D)Statement I is incorrect but Statement II is correct.

Answer: (C)

Solution

When glycerol is heated with a dehydrating agent such as potassium hydrogen sulphate it loses two molecules of water and is converted into acrolein, ; this conversion is the basis of the standard acrolein test for glycerol, so the first statement is sound. The description of the smell, however, is not: acrolein is known for a sharp, pungent and irritating odour, not a fruity one, so the second statement is false even though acrolein formation genuinely does serve to detect glycerol. The first statement is thus correct and the second incorrect.

JEE Main · 2022 · 25 Jul 2022 · Shift 1 · Single correct option

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