Question

in which of the following process chemical changes occurs. 1)evaporation 2)burning 3)moisturaisation
4)boiling

Answer 1

A chemical change occurs when one substance gets converted into another due to a chemical process. This change is very often not reversible.

Among the given options, the process that causes a chemical change is 2) burning. When a substance is burnt, it cannot be restored to its original form. For example, when a paper is burnt, it is converted to ashes. It is not possible to reconvert the ash into paper.

Answer 2

During a chemical change , always a new product is formed with different composition.
ENERGY May be given out or absorbed during chemical change .
So, among the above given options:

Burning involves chemical changes.

Example:
Burning of candle:
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Candle burns to give heat , light energy along with water vapour and CO2.
It's irreversible change.

Remaining options are physical change examples
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