Question

Why are aldehydes and ketones polar compounds?

Answer 1

Chemical compounds are classified into polar and nonpolar compounds depending upon the atoms present in them. When a molecule consists of atoms with electronegativity difference then the more electronegative atom attracts electrons from less electronegative atoms leading to the polarity or movement of electrons in that molecule.

Complete answer:
Electronegativity is defined as the tendency of attraction of a shared pair of electrons towards itself. Oxygen has the electronegativity of $3.44$ whereas carbon has the electronegativity of $2.55$ . These two atoms have a difference in the values of electronegativity.
Chemical compounds are classified into functional groups based on the groups present in it. carbonyl compounds are the compounds consisting of a carbonyl group $\left( {C = O} \right)$ .
Aldehydes and ketones are the two functional groups that consist of a carbonyl group. In aldehydes, the carbonyl groups are attached to one alkyl group or carbon atom which is a part of the alkyl group, and a hydrogen atom. In ketones, the carbonyl groups are attached to two alkyl groups.
Due to the difference in the electronegativity of carbon and hydrogen atoms, oxygen attracts electrons from carbon which leads to the polarity of a molecule. Thus, aldehydes and ketones are termed polar compounds.

Note:
Some of the examples of polar compounds other than aldehydes and ketones are alcohols. As alcohols consist of a hydrogen atom and oxygen in their functional group. Thus, the values of electronegativity must be considered while classifying the compounds as polar and non-polar.