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A strong base can abstract an $\alpha$-hydrogen from:
A
ketone
B
alkane
C
alkene
D
amine
Detailed Solution
The hydrogen atoms on the carbon next to a carbonyl group ($\alpha$-hydrogens) are acidic.
The carbonyl group is strongly electron withdrawing, and the carbanion formed after the loss of the $\alpha$-hydrogen is stabilised by resonance with the $C=O$ group (enolate ion).
$R-CO-CH_3 + B^- \rightarrow R-CO-\overset{\ominus}{C}H_2 \leftrightarrow R-C(O^-)=CH_2 + BH$
So a strong base can abstract an $\alpha$-hydrogen from aldehydes and ketones to form a carbanion or the enolate ion. This is the first step of reactions like the aldol condensation.
In alkanes, alkenes and amines there is no such resonance stabilisation of the resulting carbanion, so their C-H hydrogens are not acidic enough to be removed in this way.
Hence the answer is ketone.
The carbonyl group is strongly electron withdrawing, and the carbanion formed after the loss of the $\alpha$-hydrogen is stabilised by resonance with the $C=O$ group (enolate ion).
$R-CO-CH_3 + B^- \rightarrow R-CO-\overset{\ominus}{C}H_2 \leftrightarrow R-C(O^-)=CH_2 + BH$
So a strong base can abstract an $\alpha$-hydrogen from aldehydes and ketones to form a carbanion or the enolate ion. This is the first step of reactions like the aldol condensation.
In alkanes, alkenes and amines there is no such resonance stabilisation of the resulting carbanion, so their C-H hydrogens are not acidic enough to be removed in this way.
Hence the answer is ketone.