Single correct option
Benzaldehyde is treated with excess formaldehyde in concentrated aqueous . The major organic products after the reaction (and before acidification) are
- A. Sodium formate and benzyl alcohol
- B. Sodium benzoate and methanol
- C. Sodium benzoate and benzyl alcohol
- D. Sodium formate and sodium benzoate
Show answer and solution
Answer: (A) Sodium formate and benzyl alcohol
Neither aldehyde has an -hydrogen, so a crossed Cannizzaro reaction occurs. Hydroxide adds to the more electrophilic, unhindered , and the resulting hydrate anion transfers hydride to the other aldehyde (benzaldehyde) which is reduced. So formaldehyde is oxidised to formate and benzaldehyde is reduced to benzyl alkoxide, giving benzyl alcohol: .
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