Question

In which one of the following situations a chemical reaction does not occur?

• A. Milk is left open at room temperature during summer
• B. Grapes get fermented
• C. An iron nail is left exposed to humid atmosphere
• D. Melting of glaciers

Hint:

A physical change involves a change in state or appearance without changing the chemical identity, such as the melting of glaciers.

Answer 1

The Correct Option is D

Option (1) describes milk left open at room temperature; bacterial fermentation occurs, a chemical process.
Option (2) involves grape fermentation, a metabolic chemical reaction.
Option (3) concerns an iron nail exposed to a humid environment, leading to rust (iron oxide) formation via a chemical reaction.
Option (4) describes the melting of glaciers, a physical change lacking new substance formation.
Therefore, the accurate answer is option (4).