Question

When con. sulphuric acid is added to sugar crystals in a test tube, white sugar changes to black residue.

This is due to the

A) Drying property of hydrogen.

B) Removal of water of crystallization

C) Dehydrating property of Con. Sulphuric acid, in which the hydrogen and oxygen present in sugar are removed in

the form of water.

D) All the above.

E) None.
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Answer 1

Answer:

C. Dehydrating property of con. Sulphuric acid

Explanation:

Sulfuric acid is a super-strong dehydrating agent, it sucks up water, or the components needed to produce it. Hence, the ether groups (-C-O-C-) and hydroxyl groups (-OH) in sucrose are stripped away. The overall reaction is written:

C₁₂H₂₂O₁₁ → 11 H₂O↑ + 12 C