(a) State the law that is followed by balancing a chemical equation.(b) Balance the following chemical equation: Na + H3O → NaOH + H2

(a) The law that is followed by balancing a chemical equation is the Law of Conservation of Mass. This law states that matter cannot be created or destroyed. In chemical reactions, the total mass of the reactants (the substances that are combined) must equal the total mass of the products (the substances that are formed). This is why we balance chemical equations - to ensure that the same number of each type of atom is present on both sides of the equation.

(b) To balance the chemical equation Na + H3O → NaOH + H2, we need to ensure that the number of atoms of each element is the same on both sides of the equation.

Here's how to do it:

1. Write down the number of atoms for each element in the reactants and the products:

   Reactants: 1 Na, 3 H, 1 O Products: 1 Na, 2 H, 1 O, 1 H

2. It's clear that we have one extra hydrogen atom on the reactant side. To balance this, we can add a coefficient of 2 in front of H2 on the product side:

   Na + H3O → NaOH + 2H2

3. Now, count the atoms again:

   Reactants: 1 Na, 3 H, 1 O Products: 1 Na, 4 H, 1 O

4. Now we have one extra hydrogen atom on the product side. To balance this, we can add a coefficient of 2 in front of H3O on the reactant side:

   Na + 2H3O → NaOH + 2H2

5. Count the atoms one last time:

   Reactants: 1 Na, 6 H, 2 O Products: 1 Na, 4 H, 1 O

6. We still have an imbalance in hydrogen and oxygen atoms. To correct this, we can add a coefficient of 2 in front of NaOH on the product side:

   Na + 2H3O → 2NaOH + 2H2

7. Count the atoms one last time:

   Reactants: 1 Na, 6 H, 2 O Products: 2 Na, 6 H, 2 O

Now, the equation is balanced. The balanced chemical equation is:

Na + 2H3O → 2NaOH + 2H2