What visible change is observed in limewater (colourless) when ${\text{CO}}_2$ gas is passed through it?

Q. What visible change is observed in limewater (colourless) when ${\text{CO}}_2$ gas is passed through it?

Q. A green solution of potassium manganate (VI) turns purple and a brown solid is precipitated, when $C{O}_2$ gas is bubbled through the solution.

The above change is observed when $C{O}_2$ gas is passed into an aqueous solution of the given ion. The function of $C{O}_2$ is:

Q. Take an aqueous sodium bicarbonate solution in a test tube and heat it above ${80}^{o}C$. What do you observe if the evolved gas is passed through lime water?

Q. What is the reason why chlorine gas turns colourless potassium bromide solution to coloured?

Q. When an aluminium strip is kept immersed in freshly prepared ferrous sulphate solution taken in a test tube, the change which is observed is:
(1) light green solution slowly turns colourless
(2) the lower end of the test tube becomes slightly warm
(3) a colourless gas with smell of burning sulphur is observed
(4) light green solution changes to blue