Blance NH3+Na--->NaNH2+H2

2NH3 + 2Na —> 2NaNH2 + H2

Explanation:

NH3 + Na —> NaNH2 + H2

The above can be balance by doing the following:

There are a total of 4 hydrogen atoms on the right and 3 atoms on the left. This can be balance by putting 2 in front of NH3 and 2 in front of NaNH2 as shown below:

2NH3 + Na —> 2NaNH2 + H2

There are 2 atoms of Na on the right and 1 atom on the left. It can be balance by putting 2 in front of Na as shown below

2NH3 + 2Na —> 2NaNH2 + H2

Now we can see that the equation is balanced as we have equal numbers of atoms of the different elements on both sides of the equation.

i'm assuming that it's c.) red bank..