Question

Boojho took an empty plastic bottle, turned it upside down and dipped its mouth into a bucket filled with water. He then tilted the bottle slightly and made the following observations:
(i) Bubbles of air came out from the bottle.
(ii) Some water entered the bottle.
(iii) Nitrogen gas came out in the form of bubbles and oxygen got dissolved in water.
(iv) No bubbles formed, only water entered the bottle.
Which observation(s) is/are correct?

• A. (i) and (ii)
• B. (iv) only
• C. (iii) and (iv)
• D. (i) only

Answer 1

The correct option is A

(i) and (ii)

The correct option is A.
The explanation for the correct option:
Statement (i):

1. Although air is present everywhere, we cannot see it with the human eye since it is invisible.
2. As a result, the air that was present created bubbles.

Statement (ii):

1. A small amount of water entered the bottle as a result of the bottle tilting, causing air bubbles to escape.
2. When the bottle was tilted, the air was released as bubbles, and the empty space that the air had occupied was filled with water.
3. This activity demonstrates how air takes up space.
4. It completely fills the bottle and it surrounds us in every direction.
5. Since the bucket was already full of water, air bubbles sprang from the omnipresent but unseen substance, and water entered the bottle as a result.

Explanations for the incorrect options:
Statement (iii):

1. Oxygen and nitrogen are found in the air together.
2. They cannot be distinguished with naked eye and an observation that Nitrogen gas came out in the form of bubbles and oxygen got dissolved in water is not possible.

Statement (iv):

1. Escaping air from the bottle results in formation of bubbles.
2. Therefore along with entry of water into the bottle, bubble will also be formed.

Final answer: Bubbles of air came out from the bottle and some water entered the bottle is the correct observation.