Question

Write a balanced chemical equation from the following information: An aqueous calcium hydroxide solution (lime water) reacts with carbon dioxide gas to produce a solid calcium carbonate precipitate and water.

Answer 1

Hint: As we know that calcium hydroxide solution is also known as slaked lime or lime water solution. Its chemical formula is $Ca{{(OH)}_{2}}$. It is a strong base as it releases hydroxide ions ($O{{H}^{-}}$ ) in aqueous medium. So here we have to write the chemical equation of the reaction between calcium hydroxide solution with carbon dioxide.

Complete answer:
Let us discuss about calcium hydroxide followed by its reaction with carbon dioxide gas as follows:-
-Calcium hydroxide: It is also known as slaked lime or lime water and its chemical formula is$Ca{{(OH)}_{2}}$. It has various uses and applications in cement and marble manufacturing industries.
When it reacts with carbon dioxide gas, it produces a solid calcium carbonate as precipitate and water as shown below:-
$Ca{{(OH)}_{2}}+C{{O}_{2}}\to CaC{{O}_{3}}+{{H}_{2}}O$
The colour of the solution turns milky white due to the precipitation of calcium carbonate which is white in colour.
-The balancing of above chemical equation is done as follows:-
We will compare the number of atoms of different elements on both reactant and product side so as to check whether the mass on both sides of the reaction is equal or not.

Reactant side:-	Product side:-
Ca = 1	Ca = 1
H = 2	H = 2
O = 4	O = 4
C = 1	C = 1

As we can see that each number of atoms of different elements is the same on both sides, therefore we do not need to balance it and it will be considered as a balanced equation.
-So the balanced chemical equation is: $Ca{{(OH)}_{2}}+C{{O}_{2}}\to CaC{{O}_{3}}+{{H}_{2}}O$.

Note:
-Remember to check the atoms on both sides of the reaction while balancing a chemical equation because according to the law of conservation mass, “the mass can neither be created, nor destroyed” which means total mass of all the compounds on reactant and product side should be equal.
-Also if carbon dioxide gas is continuously passed through calcium hydroxide solution, the lateral milky colour disappears due to the formation of calcium bicarbonate in the solution (due to the reaction with water produced in it).