In the ferric reduction method, what color is the product formed after reaction with glucose?

• A. Yellow-orange
• B. Colorless
• C. Blue
• D. Green

Answer: (B)

Glucose donates electrons to ferric ions, turning Fe3+ into Fe2+. In this ferric reduction setup, the immediate product is Fe2+ in solution, and without forming any colored complex, Fe2+ itself is colorless. Colors like yellow-orange, blue, or green arise only after additional complexation or subsequent reactions that introduce a chromophore. Since the reduced product here remains uncomplexed Fe2+ and therefore colorless, the correct choice is colorless.