Question

Which of the following changes can be generally reversed?

• A. Physical change
• B. Chemical change
• C. Either a or b
• D. None of these

Answer 1

The correct option is A

Physical change

The explanation for the correct option

Option(A):

Physical change: It is a type of change in which there is no change in the chemical properties of the substance and no new substance is formed.

• It is a type of reversible change
• Reversible change: It is a type of change that can be reversed easily
• For example Melting of ice, freezing of water, etc.

The explanation for the incorrect options:

Option (B)

Chemical change: It is a type of change in which there is a change in the chemical properties of the substance and a new substance is formed.

• It is a type of irreversible change
• Irreversible change: It is a type of change that cannot be reversed.
• Heat will be released or absorbed in this type of reaction.
• For example, Magnesium($\mathrm{Mg}$) when reacted with Oxygen(${\mathrm{O}}_2$) results in the production of Magnesium oxide($\mathrm{MgO}$), and energy is released in the form of light.
• $\underset{\mathrm{Magnesium}}{\mathrm{Mg}\left(\mathrm{s}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{Magnesium}\mathrm{Oxide}}{\mathrm{MgO}\left(\mathrm{s}\right)}+\mathrm{light}$
• Therefore can't be reversed.

Option (C)

• Only physical changes can be reversed.

Therefore, the correct option is an option (A)