What Volume (L)of NH₃ Gas at STP Is Produced by the Complete

Multiple Choice

What volume (L) of NH₃ gas at STP is produced by the complete reaction of 7.5 g of H₂O according to the following reaction?
Mg₃N₂ (s) + 6H₂O (l) → 3Mg(OH) ₂ (aq) + 2NH₃ (g)

A) 3.1
B) 9.3
C) 19
D) 28
E) 0.32