Question

Which of them is not the characteristics of a physical change?
A.Change in the physical properties
B.New substances are formed
C.Reversible reaction
D.Original substance can be reverted back

Answer 1

Hint:First we will take a look at all the characteristics of a physical change. The characteristics which don't match then properties mentioned in the options, will be the correct option. Physical changes only change the appearance of a substance, not its chemical composition.

Complete answer:
Chemists make a distinction between two different types of changes that they study i.e. physical changes and chemical changes.
A physical change is a change to the physical—as opposed to chemical—properties of a substance. They are usually reversible. The physical properties of a substance include such characteristics as shape, volume and size, colour, texture, flexibility, density, and mass. Cutting, tearing, shattering, grinding, and mixing are some examples of physical changes because they change the form but not the composition of a material.
A chemical change happens when one chemical substance is transformed into one or more different substances, in this, a new substance can be formed. Rotting, burning, cooking, and rusting are the examples of chemical changes because they produce substances that are entirely new chemical compounds.
Let’s take a look at some of the properties of a physical change:
A physical change is temporary and is usually reversible.
No new substances are formed during a physical change.
There is no change in mass of the substance during a physical change.
There is no net absorption or release of energy during a physical change.

Thus, the correct answer is option (B).
Note:
In a reversible physical change, the original form of the matter can be restored and in an irreversible physical change, the original form cannot be restored.