Question

The experimental set up shown here to demonstrate that ‘CO₂ is given out during respiration’, did not yield expected results because :



(1) the flask was not air tight
(2) there was no KOH in test tube in the flask
(3) the delivery tube was dipped in water
(4) the germinating seeds were not immersed in water

Answer 1

The above experiment did not yield the desired results as there was no KOH tube in the flask. KOH absorbs CO₂ and creates partial vacuum in the flask which leads to increase in the water level in the delivery tube. The increase in the water level in the bent tube is an indication that
CO₂ is produced during respiration.

The correct set up is



Hence, the correct answer is option 2.