Question

Which of the following is not a chemical change?

• A. Photosynthesis
• B. Breaking a glass tumbler
• C. Burning of wood
• D. Rusting of iron

Answer 1

The correct option is B

Breaking a glass tumbler

Answer:

Chemical change: These changes are the results of chemical reactions. New substances are formed during this change.

Physical change: In these changes matter changes its physical properties only. No new substances are formed during this change.

The explanation for the right answer:

Option B: Breaking a glass tumbler

• Breaking of glass tumbler is an example of physical change because the broken pieces of glass are not a new substance.
• So, option B is the right answer.

The explanations for the wrong answers:

Option A: Photosynthesis

• Photosynthesis is a chemical change in which a new substance is formed.
• The chemical reaction involved in it is given below.
• $$\begin{gathered} 6{\mathrm{CO}}_2\left(\mathrm{g}\right)+6{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\underset{\mathrm{Chlorophyll}}{\overset{\mathrm{Sunlight}}{\to }}{\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6\left(\mathrm{s}\right)+6{\mathrm{O}}_2\left(\mathrm{g}\right) \\ (\mathrm{Carbon}\mathrm{dioxide})\left(\mathrm{Water}\right)\left(\mathrm{Glucose}\right)\left(\mathrm{Oxygen}\right) \end{gathered}$$
• So, option A is the wrong answer.

Option C: Burning of wood

• Burning of wood is a chemical change in which a new substance is formed.
• Burning of anything involves the reaction of that substance with oxygen.
• So, option C is the wrong answer.

Option D: Rusting of Iron$\left(\mathrm{Cu}\right)$

• Rusting of iron is a chemical change in which new substance rust is formed.
• The chemical reaction involved in it is given below.
• $$\begin{gathered} 4\mathrm{Fe}\left(\mathrm{s}\right)+3{\mathrm{O}}_2\left(\mathrm{g}\right)+{\mathrm{XH}}_2\mathrm{O}\left(\mathrm{aq}\right)\to 2{\mathrm{Fe}}_2{\mathrm{O}}_3.{\mathrm{XH}}_2\mathrm{O}\left(\mathrm{s}\right) \\ \left(\mathrm{Iron}\right)\left(\mathrm{Air}\right)\left(\mathrm{water}\right)\left(\mathrm{Rust}\right) \end{gathered}$$
• So, option D is the wrong answer.

Conclusion:

So, the Breaking of the glass tumbler is not an example of physical change

Therefore, the right answer is option B.