First, let's find the number of moles of ammonium nitrite.
0.5 mol/L * 1.20 L = 0.6 mol
The decomposition reaction is
NH₄NO₂ → N₂ + 2 H₂O
Let's calculate the amount of N₂ gas produced.
0.6 mol * 1 mol N₂/1 mol NH₄NO₂ = 0.6 mol N₂
Then, let's compute P through the ideal gas equation:
P = nRT/V
P = (0.6)(0.0821 L-atm/mol-K)(25+273 K)/10 L
P = 1.47 atm
