How can one differentiate between the organic compounds propanal (CH3CH2CHO) and propanone (CH3COCH3)?

React a sample of each compound with Tollens reagent. The aldehyde (propanal) will be oxidised to a carboxylic acid (propanooic acid) and will form a silver mirror. No change will be observed with the ketone or alternatively Heat a sample of each compound with a solution of acidified potassium dichromate, which is orange. Again, the aldehyde will have been oxidised to a carboxylic acid, and the solution will turn green. The ketone solution will stay orange