Question

A strong base can abstract \[\text{ }\alpha\text{ -}\] hydrogen from:
A.Alkane
B.Alkene
C.Amine
D.Ketone

Answer 1

Hint: The \[\text{ }\alpha\text{ -}\] hydrogen in an organic molecule is the first hydrogen atom attached to the carbon atom bonded to the functional group in the molecule, such as carbonyl, carboxyl, etc. It can be abstracted when the functional group contains a carbonyl group.

Complete answer:
The alpha carbon atom is the carbon atom that is attached to a functional group in a molecule and the hydrogen atom next to the alpha carbon atom is the alpha hydrogen atom. The alpha carbon atom is acidic in nature as it is bonded to an electron deficient carbon atom which draws the shared pair of electrons between the hydrogen atom and the alpha carbon atom more towards itself. Since it is acidic in nature, that hydrogen atom can be abstracted as a proton by any basic substance.
The compounds from which the alpha hydrogen atom can be abstracted should have an electronegative group attached to the carbon atom so that the alpha carbon atom becomes electron-deficient. Thus among the given compounds, the ones that have electron deficient carbon atoms are the “ketone” group.

Thus, the correct answer is option D.

Note:
Examples of compounds containing alpha carbon atoms include the carbonyl compounds, such as the aldehydes, ketones, carboxylic acids, etc. in these compounds due to the unequal sharing of electrons between the carbonyl carbon and the oxygen atom is the reason behind the acidic nature of alpha hydrogen atom.
These compounds after giving away the alpha hydrogen atom form a double bond between the beta carbon and the alpha carbon which often stabilizes the molecule.