Nitrogen oxide is a pollutant commonly found in
smokestackemissions. one way to remove it is to react it with
ammonia.
how many liters of ammonia are required to change 12.8l of
nitrogenoxide to nitrogen gas? assume 100% yield and that all gases
aremeasured at the same temperature and pressure.

You need 8,53 L of ammonia

Explanation:

Global reaction of remotion of nitrogen oxide with ammonia is:

4 NH₃ + 6 NO ⇒ 5 N₂ + 6 H₂O

This balanced equation shows that 4 NH₃ moles reacts with 6 NO moles.

With 100% yield and temperature and pressure constants it is possible to apply Avogadro's law. This law is an experimental gas law relating the volume of a gas to the amount of substance of gas present. The formula is:

Where:

V₁ is the NO volume =  12,8L

n₁ are NO moles = 6

n₂ are NH₃ moles = 4

V₂ is NH₃ volume, the unknown.

Thus, V₂ are 8,53 L of ammonia

I hope it helps!