Question

Write the reactions of glucose with Fehling’s solution and Tollen’s reagent.

Answer 1

(i) Reaction with Fehling’s Solution:

A deep blue solution is obtained by mixing Fehling A (aqueous CuSO₄ solution) and Fehling B (aqueous NaOH solution containing a small amount of Roschelle’s salt) in equal volumes. When heated with glucose then Fehling solution gives a red precipitate.

(ii) Reaction with Tollen’s Reagent:

Tollen’s reagent is ammonical silver nitrate solution. When heated with glucose in a clean test tube, a shining mirror gets deposited at the bottom of the tube.
AgNO₃ + NH₄OH → AgOH + NH₄NO₃