Question

ammonia gas can be produced by heating together the solid NH4Cl and calcium hydroxide. If a mixture containing 100g of each of these solids is heated, how many grams of NH3 are produced? also find the volume of NH3 gas at STP.
2NH4Cl + Ca(OH)^2___》2NH3 + CaCl2 + 2H2O

Answer 1

2NH₄Cl + Ca(OH)₂  →  2NH₃ + CaCl₂ + 2H₂O

Now 2 moles of ammonia is produced from 2 moles of ammonium chloride and 1 mole of calcium hydroxide.

Moles of ammonium chloride of = 100 / 53.5 = 1.86
Moles of calcium hydroxide = 100/ 74 =  = 1.35

We need to find limiting reagent.

1 mole of cal. hydr. reacts with 2 moles of ammo. chl.
So 1.35 moles of cal.hyd. requires 1.35 x 2 = 2.7 moles of ammo.chl.
which is not accessible.

Hence Calcium hydroxide is not limiting reagent.

2 moles of ammonium chloride reacts with 1 mole of calcium hydroxide
So 1.86 of amm.chl. requires 1.86/2 = 0.93 moles of cal.hydr.
, which is available.
So ammonium chloride  is limiting reagent.

Unreacted moles of calcium hydroxide = 1.35 - 0.93 = 0.42 moles

Now, 2 moles of ammonia are formed from 2 moles of ammonium chloride.
Therefore 1.86 moles would be formed from 1.86 moles of ammonium chloride .

Weight of ammonia produced = 1.86 x 17 = 31.62 gm

1 mole of ammonia measures 22.4 L at STP
1.86 mole would measure 1.86 x 22.4 = 41.664 L at STP.

Hope my answer is correct.