Question

In sugar test greenish or brownish precipitate appears give reason

Answer 1

Answer:

its brownish in colour

Answer 2

The reason for the appearance of greenish or brownish precipitate in sugar test is the reduction of copper (II) ions to copper (I) ions.

Explanation:

• The test which is used to detect the presence of sugar or carbohydrate in the given sample is called Benedict's test or sugar test.
• The reagent used in this test is called Benedict's reagent and it has copper (II) ions.
• When the test sample is heated with Benedict's reagent, the copper(II) ions are reduced by the sugars present in the sample into copper (I) ions.
• If high sugar is present in the sample it leads to the formation of a brick red color precipitate, whereas if only trace amount of sugar is present it leads to greenish or brown precipitate, no sugar means the solution remains blue.
• Thus it can be inferred that, due to the presence of a trace amount of sugar in, the sample gives a greenish or brownish precipitate.