Answer:
3 moles
Step-by-step explanation:
The balanced equation for the reaction is given below below:
N2(g) 3H2(g) --> 2NH3(g)
From the balanced equation above,
1 mole of N2 required 3 moles of H2.
Therefore, Xmol of N2 will require 9 moles of H2 i.e
Xmol of N2 = 9/3
Xmol of N2 = 3 moles
From the calculations made above, 3 moles of nitrogen (N2) is needed to completely convert 9.0 mol hydrogen gas(H2) to ammonia gas (NH3)