Aldehydes and ketones can be prepared by:

(A) Oxidation of Alcohol
(B) Dehydrogenation of Alcohol
(C) Ozonolysis of alkenes
(D) Hydration of Alkyne

Choose the correct answer from the options given below:

(A), (B), (C) and (D)

The correct answer is Option (2) → (A), (B), (C) and (D)

Some important methods for the preparation of aldehydes and ketones are as follows:

By oxidation of alcohols: Aldehydes and ketones are generally prepared by oxidation of primary and secondary alcohols

By dehydrogenation of alcohols: In this method alcohol vapours are passed over heavy metal catalysts (Ag or Cu). 

By ozonolysis of alkenes: ozonolysis of alkenes followed by reaction with zinc dust and water gives 

By hydration of alkynes: Addition of water to ethyne in the presence of $H_2SO_4$ and $HgSO_4$ gives acetaldehyde. All other alkynes give ketones in this reaction.

Aldehydes and ketones can be prepared by all the given methods.