Final answer:
To differentiate ethanal and propanal, chemical tests such as the Silver Mirror Test (Tollens' reagent) and Fehling's test can be used, with ethanal reacting faster in both due to its higher reactivity.
Step-by-step explanation:
To distinguish between ethanal and propanal, both of which are aldehydes, you can perform a simple chemical test known as the Silver Mirror Test, which is a part of Tollens' reagent reaction. This test exploits the fact that aldehydes can be easily oxidized. When reacting with Tollens' reagent, aldehydes reduce the silver (I) ion to metallic silver, forming a shiny silver mirror-like coating on the test tube's surface.
Ethanal will give a positive Tollens' test more rapidly compared to propanal due to ethanal's higher reactivity. Another test to differentiate them is the Fehling's test, which uses a copper (II) complex. Ethanal, being more reactive, will also respond faster to this test, reducing the copper (II) ion to copper (I) oxide, which precipitates as a red solid.
When performing any chemical experiment, safety should always be a priority. Make sure to wear appropriate protective gear and conduct tests in a well-ventilated area or under a fume hood.