Answer:
Nitrogen oxide is compound.
Explanation:
Compound is defined as chemical substance made up two or more than two different elements. For example : NaOH is the compound made up of 1 sodium atom, 1 oxygen atom and 1 hydrogen atom.
Now, according to the question, out iron and nitrogen oxide. Nitrogen dioxide (NO)is a compound because its made up of one nitrogen atom and 1 oxygen atom.
Where as iron is not a compound because it is just composed of iron atoms only.
