answer and explanation
NH₄NO₂ -> N₂ + 2H₂0
when we look at the reaction equation we see that 2 mols of water are produced for every 1 mol of nitrogen gas
a. we know that 1 mol of any gas at STP will occupy a volume of 22.4L
therefore 50.0L/22.4L/mol = 2.23 mols
there are 2.23 mols of water and when we look at the balanced equation the mol ratio of nitrogen gas to water vapour is 1:2
therefor 1/2 x 2.23 = 1.12 mol of nitrogen gas will be present
the volume will be
1.12 mols x 22.4L/mol
= 25.01L of N₂ will be produced