Question

(i) Why do we keep the conical flask airtight?

Answer 1

because the airport not enter in airtight container which is called conical flask

Answer 2

Conical Flask is airtight

Explanation:

An experiment was conducted to demonstrate that seeds released carbon dioxide. So they took a test tube with Potassium Hydroxide (KOH) and some germinating seeds and placed them inside an air-tight conical flask. The conical flask was used to make sure that no outside air entered the experiment.  

Now, the seeds would release CO2 which will be absorbed by KOH. So a partial vacuum will be created inside the flask. This will cause equal volume of water to rise up in the tube.  

KOH + CO2 —-> K2CO3 +H20

This shows that the germinating seeds are respiring out carbon dioxide.