Electronically, aldehydes are more reactive than ketones because of the greater polarization of aldehyde carbonyl groups To see this polarity difference, recall the stability order of carbocations (Section 6.10). A primary carbocation is less stable than a secondary carbocation because it has only one alkyl group inductively stabilizing the positive charge rather than two. In the same way, an aldehyde has only one alkyl group inductively stabilizing the partial positive charge on the carbonyl carbon rather than two. An aldehyde is thus more electrophilic and more reative than a ketone.