Question

Which of these results would you expect to see if you warmed propanone with Fehling’s solution? 

Answer 1

Fehling's solution is prepared by combining two separate solutions, known as Fehling's A and Fehling's B. Fehling's A is aqueous solution of copper(II) sulfate, which is deep blue. Fehling's B is a colorless solution of aqueous Potassium sodium tartrate (also known as Rochelle salt) made in a strong alkali, commonly with sodium hydroxide. Typically, the L-tartrate salt is used. The copper(II) complex in Fehling's solution is an oxidizing agent and the active reagent in the test.

The deep blue active ingredient in Fehling's solution is the bis(tartrate) complex of Cu2+. The tartrate tetraanions serve as bidentate alkoxide ligands.