Answer
Calcium oxide is the limiting reactant.
$68.1\ g\ NH_3$
Work Step by Step
Number of moles of the reactants:
Calcium oxide: $112\ g\div 56.08\ g/mol=2.00\ mol$
Ammonium chloride: $224\ g\div 53.49\ g/mol=4.19\ mol$
Ratio: $4.19/2.00=2.09$
Calcium oxide is the limiting reactant.
From stoichiometry:
$2.00\ mol\times 2_{NH_3}/1_{CaO} \times 17.03\ g/mol\ NH_3=68.1\ g\ NH_3$
