Answer
$1$ volume of $NO$
Work Step by Step
The balance chemical equation for the given chemical reaction is written as
$4NH_3(g)+5O_2(g)\rightarrow 4NO(g)+6H_2O(g)$
This reaction shows that $4$ volumes of $NH_3$ produce $4$ volumes of $NO$, thus $1$ volume of $NH_3$ will produce $1$ volume of $NO$.
