Answer:
Order zero
Explanation:
Let's consider the decomposition of ammonia to nitrogen and hydrogen on a tungsten filament at 800°C.
2 NH₃(g) → N₂(g) + 3 H₂(g)
The generic rate law is:
rate = k × [NH₃]ⁿ
where,
rate: reaction rate
k: rate constant
n: reaction order
When n = 0, we get:
rate = k × [NH₃]⁰ = k
As we can see, when the reaction order with respect to ammonia is zero, the reaction rate is independent of the concentration of ammonia.