Chemistry
Assertion (A): When a change in a substance can be reversed by changing the conditions, it is said to be a reversible and temporary change.
Reason (R): Burning a piece of paper is a reversible change.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false
- A is false but R is true.
Phy & Chem Changes
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Answer
A is true but R is false
Explanation — Burning a piece of paper is an irreversible change as a new substance ash is formed.
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Related Questions
In a chemical change :
- a new substance is formed
- energy is either released or absorbed
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- all of the above
Assertion (A): The changes which result in the formation of new substances with entirely different composition and properties are called chemical changes.
Reason (R): Chemical changes are permanent and irreversible.
- Both A and R are true and R is the correct explanation of A.
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Assertion (A): Sublimation of camphor is a physical change.
Reason (R): No new substance is formed.
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Assertion (A): For rust formation to take place, iron must be exposed to air and water for some time.
Reason (R): Rust is a reddish brown substance formed on the surface of iron.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
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