Question

The following experiment was set up to show that a gas is given out during respiration. But there was no rise in the level of water. This was because :

• A. germinating seeds have not been kept under water in the flask
• B. water is kept in the beaker instead of lime water
• C. the cork on the flask is made of rubber
• D. no substance is kept in the flask to absorb the gas given out by seeds

Answer 1

The correct option is D

no substance is kept in the flask to absorb the gas given out by seeds

The correct option is D.

Explanation of the correct option:

• Germinating seeds respire through the aerobic mode of respiration.
• During the aerobic respiration process, carbon dioxide is released.
• In the conical flask containing germinating seeds, lack of KOH solution causes carbon dioxide to build up in the flask as carbon dioxide won't be absorbed.
• The presence of gas in the conical flask doesn't lead to a vacuum-like condition and hence no water rise in the delivery tube.

Explanation of the incorrect options:

Option A:

• Germinating seeds are the ones that lead to a seedling and then a plant. They release carbon dioxide during respiration.

Option B:

• The presence of water in the beaker does not affect the water level during the respiration experiment.

Option C:

• Cork is mostly used to block the opening of various laboratory glassware. Cork is either made of wood or rubber.

Therefore, the absence of the substance (KOH) that can absorb the carbon dioxide gas during respiration prevents the rise of water levels in the flask.