a)Ammonium salts of non-oxidative volatile acid NH3↑+ corresponding acid↑ NH3↑+HC↑ NH4HCO NH3↑+CO2↑+H2O b)Ammonium salts of non-oxidative involatile acid NH3ftacid or acid ammonium salt (H4)3PO4 3NH3↑+H3PO4 (NH4)2SO4 NH3↑+NH4HSO4 c) Ammonium salts of oxidative acid N2t+ h2O or N201+ H20 N,O: laughing gas (NH4)2 Cr2O7 N2↑+Cr2O3+4H2O NHANO N2↑+2H2O 210 NHgNO3 N2O↑+2H2O 2NHANO 2N2↑+O2↑+4H2O d) Identification of NH4 3 NHA+OHA> H2O+NH3↑ NH4+Nessler' s reagent red-brown 2.The properties of nitrous acid and nitrites: DHNO2 is a weak acid, Ka=7.2x10 2)The pure acid is unknown, even aqueous solutions of nitrous acid are unstable, decomposing when heated according to the reaction NO2+H→HNO2→N23bue)+H2O NO↑+NO2↑ 3)Most nitrites are soluble in water except AgNO2, and are poisonous and carcinogenic 4)Oxidizing-reducing properties EA: NO: 0.94 HNO2 0.996 NO NO3001NO2-046NO 第5页 2006-02-22第 5 页 2006-02-22 5 a) Ammonium salts of non-oxidative volatile acid→Δ NH3↑+ corresponding acid↑ NH4Cl→Δ NH3↑ + HCl↑ NH4HCO3→Δ NH3↑ + CO2↑ + H2O b) Ammonium salts of non-oxidative involatile acid→Δ NH3↑+acid or acid ammonium salt (NH4)3PO4→Δ 3NH3↑ + H3PO4 (NH4)2SO4→Δ NH3↑ + NH4HSO4 c) Ammonium salts of oxidative acid →Δ N2↑+ H2O or N2O↑+ H2O N2O: laughing gas (NH4)2Cr2O7 →Δ N2↑ + Cr2O3 + 4H2O NH4NO2 →Δ N2↑+ 2H2O NH4NO3 about ⎯⎯⎯→C 0 210 N2O↑+ 2H2O 2NH4NO3 > ⎯⎯→C 0 300 2N2↑ + O2↑ + 4H2O d) Identification of NH4 + ○ 1 NH4 + + OH- →Δ H2O +NH3↑ ○ 2NH4 + +Nessler’s reagent→Δ red-brown↓ 2.The properties of nitrous acid and nitrites: 1)HNO2 is a weak acid, Ka θ =7.2×10-4 2) The pure acid is unknown, even aqueous solutions of nitrous acid are unstable, decomposing when heated according to the reaction: NO2 - +H+ →HNO2→N2O3(blue)+H2O NO↑+NO2↑ 3) Most nitrites are soluble in water except AgNO2, and are poisonous and carcinogenic 4) Oxidizing-reducing properties EA θ : NO3 - 0.94 HNO2 0.996 NO EB θ : NO3 - 0.01 NO2 - -0.46 NO