Which of the following is not an indication of a chemical change?

formation of a precipitate

formation of a gas

the container gets hot

the substance dissolves

Answer: the substance dissolves

Explanation: Chemical change is the change in which chemical composition of the substance changes.

Chemical changes are accompanied by following changes:

a) formation of precipitate

b) release or absorption of energy

c) formation of gas

d) change in color

When a substance dissolves, it only changes its state and thus there is no change in chemical composition.

Answer: Option (d) is the correct answer.

Explanation:

A chemical change is defined as the change that results in the formation of new compounds due to change in chemical composition of reactants.

For example, when any two aqueous solutions chemically react with each other then it results in the formation of an insoluble solid that is known as a precipitate.

Also, a gas is released when two substances chemically react together.

It is known that in an exothermic reaction heat is released. So, when a container gets hot then it means two or more substance have chemically react together due to which an exothermic reaction has taken place.

On the other hand, when no change in chemical composition of reactants occur then it means no chemical change has taken place.

For example, when NaCl is dissolved in water then it dissociates into sodium and chlorine ions.

This means no new compound has formed. As by evaporating water, crystals of NaCl can be formed again.

So, when a substance dissolves in water then it means no chemical change has taken place unless and until a new compound is not formed.

Thus, we can conclude that the substance dissolves is not an indication of a chemical change.