2NaNH2+N2O→NaN3+NH3+NaOH and NaN3+12H2SO4→HN3+12Na2SO4
NaNO2+12H2SO4 in situ −−−−−→HNO2+12Na2SO4 and HNO2+N2H4→HN3+2H2O
From the balanced reaction, 0.2 moles of N2O will produce 0.2 moles of HN3, and 0.6 moles of NaNO2 will produce 0.6 moles of HN3 (B).
Hence, total moles of B formed = 0.8 moles = 800 mmoles.