Question

What happens when carbon dioxide gas is bubbled through lime water?

Answer 1

Hint: As we know that the formula of lime water is $Ca{{\left( OH \right)}_{2}}$ that is also called calcium hydroxide. When carbon dioxide gas is bubbled through lime water, an insoluble precipitate is formed, due to which the colour of the solution seems to be milky.

Complete answer:
- As we know that the formula of lime water is $Ca{{\left( OH \right)}_{2}}$, when carbon dioxide gas is bubbled through lime water limestone $CaC{{O}_{3}}$ is formed which is basically an insoluble precipitate and the solution is seen to be milky. Limestone is found to be economically very much important.
- We can see the reaction that takes place when carbon dioxide is added to lime water as:
\[Ca{{\left( OH \right)}_{2}}\left( aq \right)+C{{O}_{2}}\left( g \right)\to CaC{{O}_{3}}\left( s \right)+{{H}_{2}}O(g)\]
- Further, if we add more carbon dioxide, the precipitate that was formed starts dissolving. And there will be a formation of a colourless solution of $Ca{{\left( HC{{O}_{3}} \right)}_{2}}$that is called Hydrogencarbonate. We can see the reaction that takes place as:
\[CaC{{O}_{3}}\left( s \right)+C{{O}_{2}}\left( g \right)+{{H}_{2}}O(g)\to Ca{{\left( HC{{O}_{3}} \right)}_{2}}\left( aq \right)\]
- So, we should add carbon dioxide to limewater in a limited amount to get a milky white solution.

- Hence, we can conclude that limestone $CaC{{O}_{3}}$ is formed when carbon dioxide gas is bubbled through lime water.

Note: - As we know that lime water and carbon dioxide is used as a test for carbon dioxide. Limestone that is formed as a product is actually a sedimentary rock, which is used as a building material. And also used as white pigment in paints as well as in toothpastes.