Question

Balance the equation: $HN{{O}_{3}}+Ca{{\left( OH \right)}_{2}}\to Ca{{\left( N{{O}_{3}} \right)}_{2}}+{{H}_{2}}O$

Answer 1

Hint: To solve this, you have to follow the law of conservation of mass. Start by identifying the number of each of the elements on the reactant as well as the products side. You can balance the side which has a lower number of atoms by multiplying it with a number to equate it.

Complete step by step answer:
To answer this, we should remember that balancing a chemical reaction basically means that the number of elements on the reactant side will be the same as that on the product side.
To solve this question, let us discuss conservation of mass first.
The law of conservation of mass states that in a closed system, where transfer of both mass as well as energy takes place, the mass of the system will always be constant at any time as the mass of the system cannot change and can just be converted in another form. Thus, mass is neither added or removed and is only transferred from one form to another.
Now, the equation given to us is:
$HN{{O}_{3}}+Ca{{\left( OH \right)}_{2}}\to Ca{{\left( N{{O}_{3}} \right)}_{2}}+{{H}_{2}}O$
Now, to balance this equation let us start by identifying the elements on the reactant side. We know that the elements will be the same on the product side too as they are formed from these reactants only.
Firstly, in the reactant side, we have one nitrate ion whereas 2 in the product side. So, to balance it, we will multiply 2 in the reactant side. So, the equation will become -
$2HN{{O}_{3}}+Ca{{\left( OH \right)}_{2}}\to Ca{{\left( N{{O}_{3}} \right)}_{2}}+{{H}_{2}}O$
Again, we can see that oxygen is not balanced here. If we multiply 2 in ${{H}_{2}}O$ on the product's side, the reaction will be balanced. So, the final reaction will be -
$2HN{{O}_{3}}+Ca{{\left( OH \right)}_{2}}\to Ca{{\left( N{{O}_{3}} \right)}_{2}}+2{{H}_{2}}O$
Thus, the above reaction is the required balanced equation.

Note: If the above equation was given to us in ionic form instead of the elemental form, we would have to balance mass as well as the charge on both the reactant and the products side. We would have to follow the law of conservation of mass as well as charge while writing the balanced equation for the reaction.