Question & Answer: Which of the following is an example of a chemical change? Question 7 options:…..

a) Iodine sublimation: sublimation is a process where the solids evaporate directly without passing through the liquid state.
In this process, there is only physical change occurs. No chemical reaction.
Hence, it is not a chemical reaction.

b) alcohol boiling: This process is also a physical process. Here, the alcohol changing from liquid to gaseous state.

Hence, it is also not a chemical reaction.

c) Sodium chloride melting: Here also the solid sodium chloride changing its state to a liquid. This process is a physical process.
Hence, it is also not a chemical reaction.

d) Silver tarnishing: Tarnishing is a chemical process where silver reacts with the sulphur in the air to form silver sulphide.
Since the Silver is reacting with sulphur to form new chemical silver sulphide, this process is a chemical process.
Hence, it is a chemical reaction.

e) Sucrose dissolving: sucrose dissolving is also physical change because there is no net change in the sucrose molecule.
The sucrose molecule in solid form is same to that of dissolved form.
Hence, it is a physical change.

Therefore, silver tarnishing is only one chemical in the above options.