Cannizzaros reaction is not given by__________________?
Correct answer: B. acetaldehyde
- A. formaldehyde
- B. acetaldehyde
- C. benzaldehyde
- D. trimethyl acetaldehyde
Explanation
Cannizzaro reaction is shown by aldehydes that do not have an alpha hydrogen. Acetaldehyde has the structure CH3CHO and contains alpha hydrogen, so it undergoes aldol condensation instead of Cannizzaro reaction. Students may choose formaldehyde because it is the simplest aldehyde, but formaldehyde has no alpha carbon or alpha hydrogen and readily gives Cannizzaro reaction.
Last updated
About Reactivity of Aldehydes and Ketones
The polar carbonyl group makes aldehydes and ketones undergo nucleophilic addition, reduction and condensation reactions. Aldehydes are generally more reactive and oxidise readily to carboxylic acids, whereas ketones resist mild oxidation; reactions with hydrogen cyanide, sodium bisulfite and 2,4-DNP help identify their behaviour.
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 12 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
50% NaOH is used in:
A carbonyl compound with molecular formula C5H10O reacted with iodine in an alkaline solution to give a pale yellow precipitate with an antiseptic smell.The carbonyl compound is:
A diabetic person's exhaled breath contains propanone. A student tries to test the diabetes by asking the person to bubble the reagent with his exhaled breath. Which of the following reagents would give a positive result?
Acetadeftyde on oxidation by Na, Cr,O/H SO, gives:
Acetaldehyde cannot show