question_answer

Directions : In the following question more than one of the answers given may be correct. Select the correct answer and mark it according to the code:

Which of the following undergoes aldol condensation? (1) Acetaldehyde (2) Propionaldehyde (3) Trideuteroacetaldehyde (4) Benzaldehyde

A)  1, 2 and 3 are correct

B)  1 and 2 are correct

C)   2 and 4 are correct

D)  1 and 3 are correct

Correct Answer: A

Solution :

                 Carbonyl compounds having atleast one\[\alpha -H\]atom are able to undergo aldol condensation. The structures of the given compounds are as 1. \[\underset{\begin{smallmatrix}  (3\text{ }\alpha H\text{ }-atoms) \\  \,\,acetaldehyde \end{smallmatrix}}{\overset{\alpha }{\mathop{C{{H}_{3}}CHO}}}\,\]                      2. \[\underset{\begin{smallmatrix}  (2\text{ }\alpha H\text{ }-atoms) \\  propionaldehyde \end{smallmatrix}}{\overset{\alpha }{\mathop{C{{H}_{3}}C{{H}_{2}}CHO}}}\,\] 3. \[\underset{\begin{smallmatrix}  \,\,\,\,\,\,\,\,\,(3\text{ }\alpha D\text{ }-atoms) \\  trideuteroacetaldehyde  \\  (D\text{ }is\text{ }an\text{ }isotope\text{ }of\text{ }H) \end{smallmatrix}}{\overset{\alpha }{\mathop{C{{D}_{3}}CHO}}}\,\]      4. Thus, acetaldehyde, propionaldehyde and trideutero   acetaldehyde   undergo   aldol condensation and give respective aldol.