A mixture of benzaldehyde and formaldehyde on heating with aqueous NaOH solution gives:
Correct answer: A. benzyl alcohol and sodium formate.
- A. benzyl alcohol and sodium formate.
- B. sodium benzoate and methyl alcohol.
- C. sodium benzoate and sodium formate.
- D. benzyl alcohol and sodium benzoate.
Explanation
This is a crossed Cannizzaro reaction. Formaldehyde has no α-hydrogen and its carbonyl carbon is more electrophilic and less sterically hindered, so it acts as the hydride donor and is oxidised to sodium formate, while benzaldehyde is reduced to benzyl alcohol. Products: benzyl alcohol and sodium formate (option A).
Last updated
About Aldehydes and Ketones
Aldehydes and ketones contain the polar carbonyl group, but aldehydes are generally more readily oxidised and more reactive than ketones. Coverage includes preparation by oxidation or reduction routes, nucleophilic addition of reagents such as hydrogen cyanide and bisulfite, and tests that distinguish aldehydes from ketones.
Practise Aldehydes and Ketones
679 free Aldehydes and Ketones MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Chemistry questions like this
Chemistry is on 14 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.