Aldehydes and ketones are both organic compounds containing a carbonyl group C=O . The main difference between them lies in the location of the carbonyl group and the types of atoms bonded to the carbonyl carbon.In an aldehyde, the carbonyl group is located at the end of a carbon chain, and it is bonded to a hydrogen atom and an alkyl or aryl group R . The general formula for an aldehyde is R-CHO.In a ketone, the carbonyl group is located within the carbon chain, and it is bonded to two alkyl or aryl groups R . The general formula for a ketone is R-CO-R'.A simple chemical test to distinguish between aldehydes and ketones is the Tollens' test, which uses Tollens' reagent ammoniacal silver nitrate solution . The test is based on the fact that aldehydes can be easily oxidized to carboxylic acids, while ketones are generally resistant to oxidation.Procedure for Tollens' test:1. Prepare Tollens' reagent by mixing a solution of silver nitrate AgNO3 with a solution of sodium hydroxide NaOH , followed by the addition of ammonia NH3 until a clear solution is obtained.2. Add a few drops of the unknown compound either an aldehyde or a ketone to the Tollens' reagent.3. Gently heat the mixture in a water bath.If the unknown compound is an aldehyde, the Tollens' reagent will oxidize it to a carboxylic acid, and the silver ions Ag+ in the reagent will be reduced to metallic silver Ag . This will result in the formation of a silver mirror on the inner surface of the test tube, indicating a positive result for an aldehyde.If the unknown compound is a ketone, there will be no reaction with the Tollens' reagent, and no silver mirror will form. This indicates a negative result for an aldehyde and confirms the presence of a ketone.