Answer:
To determine the limiting reactant, you need to compare the amount of each reactant with the amount required to react completely with the other reactant. The reactant that runs out first is the limiting reactant.
In this case, the balanced equation for the reaction between MgSO4 and NH3 is:
MgSO4 + 2 NH3 → Mg(NH2)2SO4
From the balanced equation, we can see that 1 mole of MgSO4 reacts with 2 moles of NH3. Therefore, 3.7 moles of MgSO4 will react with (3.7 moles)(2 moles NH3/1 mole MgSO4) = 7.4 moles of NH3.
4.8 moles of NH3 is less than 7.4 moles, so NH3 is the limiting reactant.
Uday Tahlan