Question

Select the incorrect option among the following.
A. Physical change is reversible.
B. Physical change results in the formation of new substances.
C. Chemical change is permanent.
D. Physical change is accompanied by energy change.

Answer 1

Hint: In nature, there exists various types of change. Depending on the specific nature of a particular change they are classified into two distinct types. Physical changes and chemical changes. Let us discuss them and solve the given question.

Complete step-by-step answer: Let us firstly discuss physical and chemical changes.
A physical change is a change which changes the shape, size, color, texture of a given substance but does not alter its chemical properties. For example, melting ice.
A chemical change is defined as the change which when occurs changes the chemical composition of a substance. It results in the formation of entirely new substances. For example: digestion of food.
Now, let us discuss the option one by one.
A. option A. states that physical change is reversible. This statement is true as we know that physical changes only change the color, shape, state and size of a substance, therefore these changes can be easily reversed. If we change the temperature, pressure conditions then these changes can be easily reversed.
For example, when ice melts at 100 degree Celsius it is a physical change since only the state of matter is changed. Now if we freeze water at 0 degree Celsius it turns back to ice. Hence physical changes are reversible.
B. Option B states that physical change results in the formation of new substances. This statement is incorrect. This is because a new substance is formed when new bonds are formed and this involves change in the chemical structure and we know that physical changes do not alter the chemical structure of the substance, and hence they cannot result in the formation of new substances. A new substance is formed in case of chemical changes.
C. This option states that chemical change is permanent. This is the correct statement. We know that once new bonds are formed resulting in the formation of new compounds, it is very difficult to get the original compound back. Thus, chemical changes are irreversible in nature and thus are permanent.
D. This option states that physical change is accompanied by energy change. This statement is also correct. For any change to occur, there needs to be change in energy. Let us understand this with an example, we already know that melting of ice is physical change. But for melting you provide heat to ice and heat is a form of energy. Therefore, every physical and chemical change is accompanied by energy change.

Hence, option A. is the right answer.

Note: We should note that all the physical changes are generally reversible and hence their mass does not change. Also, it should be noted that most of the changes which are physical in nature involve atoms rearrangement as seen in the formation of solid crystals.