2) The mass of the ammonium hydroxide 33.6 g.
3) The mass of the calcium hydroxide is 5.18 g.
2) The balanced reaction equation is;

Number of moles of
= 50 g/105 g/mol
= 0.48 moles
If 1 moles of
reacts with 2 moles of ammonium hydroxide
0.48 moles of
reacts with 0.48 * 2/1
= 0.96 moles
Mass of the ammonium hydroxide = 0.96 moles * 35 g/mol
= 33.6 g
3) The reaction equation is;

Number of moles of phosphorus oxide = 10 g/284 g/mol
= 0.035 moles
2 moles of calcium hydroxide reacts with 1 of phosphorus oxide
x moles of calcium hydroxide reacts with 0.035 moles of phosphorus oxide
x = 2 * 0.035 /1
= 0.07 moles
Mass of the calcium hydroxide
= 0.07 moles * 74 g/mol
= 5.18 g