Question 2
What is the job of the lime water in vessel B of activity 02?
The right answer is the one marked above.
To confirm that the CO2 has been removed from the incoming air. B not changing colour proves that the KOH in vessel A did its job properly.
The CO2 given out by the frog is tested in vessel D, which comes after the frog; B comes before it. The air stream is created by drawing the water out of bottle E.