Because if they are not balanced, then the amount of reaction is not equal to the amount of the product. You must have the same ratio of atoms on both sides of the equation because we are not losing moles of each element.
A I think that a bar graph would best represent this information.
Which type of solution are you talking about?
Answer:
11.3 g of
are produced from 36.0 g of 
Explanation:
1. The balanced chemical equation is the following:

2. Use the molar mass of the
, the molar mass of the
and the stoichiometry of the balanced chemical reaction to find how many grams of
are produced:
Molar mass
= 18
Molar mass
= 17

Therefore 11.3 g of
are produced from 36.0 g of 