Question

Q.33. In an experimental set - up to demonstrate that '$C{O}_2$ is released during respiration,' Vaseline is applied to :
(a) fix the rubber stopper at the mouth of the flask
(b) the mouth of the U-shaped tube
(c) the germinating seeds
(d) the rubber stopper where the delivery tube enters and the mouth of the flask

Answer 1

Dear student,
The vaseline is used to make the conical flask airtight so that no gas can be passed.
So the most appropriate answer is option (d).
Regards