4NH₃ + 5O₂$\to$4NO + 6H₂O. When 1 mole each of NH₃ and O₂ react with each other, the incorrect statement is 

oxygen is limiting reagent

Moles of NO formed = $\frac{4}{5}$ = 0.8

Moles of NH₃ reacted = 0.8 mole 

Excess NH₃ = 1- 0.8 = 0.2

Moles of water formed = $\frac{6}{5}$=1.2 mole