Question

while combination of nitrogen and oxygen to nitric oxide is an _ change​

Answer 1

When exposed to oxygen, nitric oxide converts into nitrogen dioxide: 2 NO + O2 → 2 NO2. This conversion has been speculated as occurring via the ONOONO intermediate. In water, nitric oxide reacts with oxygen and water to form nitrous acid (HNO2).

Answer 2

Answer:

while combination of nitrogen and oxygen to nitric oxide is an chemical change​.

it cannot be reversed by physical means,it is a kind o f addition reaction

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