_________ can be used to test for reducing sugars:

CHEMISTRY

POST UTME UI

A) Iodine solution
B) bromine water
C) Fehling's solution
D) de-ionized water

Correct Answer: C) Fehling's solution

Explanation

Reducing sugars are carbohydrates that can reduce other compounds by donating electrons. Examples of reducing sugars include glucose, fructose, and maltose.

To test for the presence of reducing sugars, Fehling's solution is used. Fehling's solution is a blue-colored liquid, composed of two separate solutions: Fehling's A, which contains copper(II) sulfate, and Fehling's B, which contains potassium sodium tartrate and sodium hydroxide. When the two solutions are mixed together, a deep blue color is formed due to the copper(II) ions in the solution.

When Fehling's solution is added to a sample containing a reducing sugar and heated, the sugar reduces the copper(II) ions to copper(I) ions, which form a brick-red precipitate of copper(I) oxide. This color change confirms the presence of a reducing sugar in the sample.

The other options are not suitable for testing reducing sugars:

Option A: Iodine solution is used to test for the presence of starch, not reducing sugars. Iodine reacts with starch to form a blue-black color.

Option B: Bromine water is a test for unsaturated hydrocarbons (alkenes), not reducing sugars. Bromine water will decolorize in the presence of unsaturated hydrocarbons.

Option D: De-ionized water is a purified form of water and does not react with reducing sugars in any specific way.

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