Question

In the given figure, a burning candle is kept in the trough containing water. It is put off after some time when covered by an inverted gas jar.

What can be concluded from the above activity?

• A. Oxygen is 1/5th the volume of air.
• B. The ratio of oxygen and nitrogen in air is 1:4.
• C. Oxygen is required for burning the candle.
• D. All of the above.

Answer 1

The correct option is D All of the above.

From the given activity, we can conclude that
(i) Water level in the gas jar is 1/5th of the jar's volume which shows that the ratio of $O_2$ is 1/5th the volume of air.
(ii) This also proves that the ratio of $O_2$ and $N_2$ in the air is approximately 1:4.
(iii) Oxygen is required for burning because the flame of the candle goes off when $O_2$ is used up.