A chemist has 3 beakers, each containing a pure sample of acetone (2-propanone), isopropanol (2-propanol) and propanal. Using chemical techniques, suggest how the chemist may be able to determine which beaker contains which sample. [4]

Brady's reagent is an orange solution of 2,4-dinitrophenylhydrazine which reacts with carbonyl containing functional groups to produce an orange precipitate (2,4-dinitrophenylhydrazone derivative of the carbonyl compound). [1]Isopropanol won't form a precipitate with Brady's reagent, which allows it to be identified. [1]Acetone and propanal do form precipitates with Brady's reagent [1]. Acetone and propanal can be distinguished by: measuring the melting points of the hydrazone precipitates and comparing those with known literature values/adding Tollen's reagent, which produces a silver mirror with the propanal but not with the acetone, as ketones can't be further oxidised by silver cations but aldehydes can be oxidised to carboxylic acids. [1]

SM
Answered by Stephen M. Chemistry tutor

1947 Views

See similar Chemistry A Level tutors

Related Chemistry A Level answers

All answers ▸

Elements in the periodic table show a trend in atomic radius. State and explain the trend in atomic radius from Li to F.


Why, in the bromination of phenols, do you not need an acid catalyst like you do in the bromination of benzene?


Which molecule has the highest boiling point: methane, ammonia, water or hydrogen fluoride? Explain why.


How does Le Chatelier's Principle allow you to predict the change of the position of equilibrium for an equilibrium reaction?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences