Question

What will happen if KOH solution is not used in the small test tube in the experimental set-up to show CO₂ is produced during respiration?

• A. CO₂ will not be produced by seeds
• B. Water level will rise in bent tube
• C. CO₂ will be produced in large volume by germinating seeds
• D. (i) CO₂ produced by the germinating seeds will not be absorbed. (ii) Water level in the bent tube will not rise up.

Answer 1

The correct option is D

(i) CO₂ produced by the germinating seeds will not be absorbed.

(ii) Water level in the bent tube will not rise up.

The correct option is D

Explanation for the correct option:

1. Respiration is the process of consumption of carbohydrates to release carbon dioxide.
2. KOH (potassium hydroxide) absorbs the CO₂ (carbon dioxide) released by the germinating seeds and creates a vacuum.
3. The effect of vacuum draws up water in the bent tube.
4. The rise of the water level is due to the vacuum created in the flask.
5. In the absence of KOH, carbon dioxide will be present in the flask that will not allow the water to move into the tube.

Explanation for the incorrect options:

Option A

The production of CO₂ depends upon the seed germination and not on the presence of KOH solution in the experimental set-up.

Option B

The water level will not rise as in the absence of KOH solution in the flask, a vacuum will not be produced, and thus the water will not be drawn up the bent tube.

Option C

The amount of CO₂ produced depends upon the amount of germinating seeds, not on the absence of KOH solution in the flask.

CO₂ will not be absorbed in the absence of KOH solution, and thus the water level will not rise in the bent tube.