Question

In which of the following process a chemical reaction has taken place? 1. Ice melts into water 2. A wet shirt got dried in sunlight 3. A brown layer is formed over iron rod kept in air 4. sugar getting dissolved in water​

Answer 1

Answer:

3.

Explanation:

A brown layer is formed over iron kept in air because Water present in air reacts with iron and forms a rusty substance called iron oxide

Answer 2

Answer:

The answer is 3. A brown layer is formed over an iron rod kept in the air

Explanation:

Option 3 is an example of a chemical change.

A chemical change results in the formation of a new substance, and it is an irreversible process. When an iron rod is exposed to air, a brown film forms on top of it owing to corrosion.

The reason why others are incorrect is that they are examples of physical change.

A reversible change in properties such as texture, shape, or state is referred to as a physical change. Considering the transformation of ice into water, there is no formation of a new substance. when water is placed at a lower temperature it again changes to ice.  A physical change does not result in the formation of new material.