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How do water molecules form hydrogen bonds with aldehydes?

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oxidation of alcohols — aldehyde Alcohols may be oxidized to give aldehydes, ketones, and carboxylic acids. The oxidation of organic compounds generally increases the number of bonds from carbon to oxygen, and it may decrease the number of bonds to hydrogen.

Aldehydes contain a carbonyl group ( $C = O$ ), which is inherently polar because the electrons in the double bond are drawn more strongly toward the oxygen atom. This gives the oxygen atom a partial negative charge, making it capable of acting as an acceptor in hydrogen bonding interactions.123

When an aldehyde is in the presence of water, the oxygen atom of the carbonyl group can form hydrogen bonds with the hydrogen atoms of water molecules, which carry a partial positive charge. While aldehydes can act as hydrogen bond acceptors, they cannot act as hydrogen bond donors because they lack a hydrogen atom covalently bonded to an electronegative atom like oxygen or nitrogen.34

It is important to distinguish this physical interaction from chemical reactivity: water can also act as a nucleophile and chemically add to the carbonyl group of an aldehyde to form a gem-diol, a process that involves the formation of new covalent bonds rather than simple hydrogen bonding.56