Answer:
21.18 gm of H2
Step-by-step explanation:
First you need the reaction equation:
N2 + 3H2 ===> 2 NH3
you can see that 3/2 as many moles of H2 are required as are NH3
this would be 10.59 moles of H2 (7.06 * 3/2)
one mole of H2 = 2 gm
10.59 * 2 = 21.18 gm