Using chemical reagents in test tubes, distinguish between isomers: A CH3CO(CH2)2CHOH, B CH3CH(OH)(CH2)2CHO and C C(CH3)2OHCOCH3

  • Google+ icon
  • LinkedIn icon
  • 1317 views

Answer:

*First draw out each compounds' structural formula (an image of the "shape and arrangement of the atoms in space"), then identify all functional groups in each compound.

*Add Tollens' reagent to all three, the compound which provides a silver mirror / precipitate, is compound B. This is because B is the only one to have an aldehyde group, which is oxidised by Tollens and gives a positive result. Ketones are NOT oxidised by Tollens and so give a negative result (no mirror).

*Next, add acidified potassium dichromate, formula Cr2O72-, to all three. A and B give a positive result for this test, a colour change from orange to green, as they both have either primary or secondary alcohols. C gives a negative result, no colour change, as it has a tertiary alcohol which won't be oxidised by the dichromate.

So:

Tollens = X, Cr2O= ✓ -> Compound A

Tollens = ✓ -> Compound B

Tollens = X, Cr2O7 = X -> Compound C

Conor M. A Level Chemistry tutor, A Level Biology tutor, A Level Math...

About the author

is an online A Level Chemistry tutor with MyTutor studying at York University

Still stuck? Get one-to-one help from a personally interviewed subject specialist.

95% of our customers rate us

Browse tutors

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok