JEE Main 2016 · 10 Apr · Shift 1 · Chemistry Q55

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ChemistrySingle correct+4 / -1Question 55 of 90

The correct statement about the synthesis of erythritol ( $\ce{C(CH2OH)4}$ ) used in the preparation of PETN is :

The synthesis requires four aldol condensations between methanol and ethanol.

The synthesis requires two aldol condensations and two Cannizzaro reactions.

The synthesis requires three aldol condensations and one Cannizzaro reaction.

Alpha hydrogens of ethanol and methanol are involved in this reaction.

Answer and worked solution

Official answer: C

Pentaerythritol is made from acetaldehyde and formaldehyde: three crossed aldol additions put three $\ce{CH2OH}$ groups on the α-carbon, and a crossed Cannizzaro reaction with formaldehyde reduces the CHO to $\ce{CH2OH}$ . (The option speaks of "methanol and ethanol", but the count of reactions in (3) is right.)

Topics:Aldol and related condensations Named reactions

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JEE Main 2016 · 10 Apr · Shift 1, Chemistry question 55