Answer 1

On the basis of types of alkyl groups attached to the carbonyl carbon,
ketones are classified as
Simple or symmetrical ketones: The ketones in which both alkyl groups attached to the carbonyl carbon are identical are called simple ketones (R =R’).
Example:

Acetone

Mixed or unsymmetrical ketones: The ketones in which the two alkyl groups attached to the carbonyl carbon are different are called mixed ketones (R ≠ R’).

Ethyl methyl ketone