Question

The images show two unrelated events occurring at separate times.Which event is most likely an example of a chemical reaction?

A. Event 1 because there is a color change.
B. Event 1 because there is a release of heat and light.
C. Event 2 because the temperature is dropping in the liquid.
D. Event 2 because the blue color mixes throughout the liquid.

Answer 1

Answer: Option (A) is the correct answer.

Step-by-step explanation:

A chemical reaction is defined as the reaction which results in the formation of a new compound or substance.

For example, rusting of iron, change of color of a substance, cooking of egg etc are all chemical reactions.

In event 1, change in color occurs when both the liquids are mixed together. This means that a chemical reaction has occurred due to which there is change in color.

Whereas release of heat or light cannot be determined by looking at the diagram as there is no chemical equation.

On the other hand, event 2 depicts that two fluids of different color are mixed and therefore, we cannot determine whether a chemical reaction is taking place in it or not.

Thus, we can conclude that Event 1 is most likely an example of a chemical reaction because there is a color change.

Answer 2

Answer: The correct option is A.

Explanation: Chemical reaction is defined as the reaction when there is a formation of new substance. Indicators that help in determining the chemical reaction are:

• Change in Temperature
• Appearance or disappearance of color
• Formation of bubbles
• Formation of a precipitate
• Characteristic odor

Option A: As seen from the image, there is a color change happening in the event. So, it can be considered as a chemical reaction.

Option B: In Event 1, release of heat and light is not visible. Hence, this is not the indicator for detection of chemical reaction.

Option C: In Event 2, we cannot judge the dropping of temperature just by seeing the image. Hence, this cannot be considered as a chemical reaction.

Option D: In this, the color is not mixed throughout the liquid, which means they are not reacting and hence, is not the indicator for chemical reaction.

Therefore, option A is the correct answer.