Chemical properties: ①unstable 2HNO2=H20+N203=H20+NO+NO2 (blue) ②weak acid HNO2-H+NO2 NO+NO2 K8=6.0X104 nitrous acid (HNO2)
nitrous acid (HNO2 ) NO+NO2 Chemical properties： ② weak acid (blue) ① unstable 2 2 _ HNO H + NO + 4 _ Ka = 6.0×10 2HNO2 H2O N2O3 H2O NO NO2 + + +
·Nitrite(亚硝酸盐) Preparation:treating the acidic oxides with a base NO,+NO+NaOH->2NaNO,+H,O Properties: 1 Most nitrites are colorless and soluble in water (except for AgNO2) ②redox properties (E(HNO:/NO)=1.04V) 2NO +2I+4H->2NO+I,+2H,O 主 NO;+Fe2*+2H*->NO+Fe*+H,O 5NO,+2MnO;+6H5NO;+2Mn2*+3H,O 3 metals having low activity correspond to nitrites of low thermal stability金属活泼性差，对应亚硝酸盐稳定性差 AgNO2<NaNO2(Mt的极化力)
• Nitrite (亚硝酸盐） Preparation: treating the acidic oxides with a base NO2 + NO+ NaOH ⎯→2NaNO2 + H2 O Properties： ① Most nitrites are colorless and soluble in water (except for AgNO2 ) ③ metals having low activity correspond to nitrites of low thermal stability 金属活泼性差,对应亚硝酸盐稳定性差 主 AgNO2<NaNO2 (M+的极化力 ) ( (HNO /NO) 1.04V) A 2 E = 2NO 2I 4H 2NO I2 2H2O - - 2 + + + + + NO Fe 2H NO Fe H2O - 2 3 2 + + + + + + + 5NO 2MnO 6H 5NO 2Mn 3H2O - 2 3 - 4 - 2 + + + + + + ② redox properties
Nitric acid (HNO3) N:2S22P3,O:2S22P4 分子内氢键 N:sp2hybridization Structure:H 120° 116 130 114° Physical properties Pure nitric acid:a colorless liquid with a pungent, choking odor (density 1.53g.cm-3) Concentrated nitric acid:69%HNO3 by mass, (density 1.4g.cm3).Pure HNO;is colorless,but some acid decomposes during the preparation to give brown gas NO2 which colors the product
• Nitric acid (HNO3 ) Physical properties ： Pure nitric acid：a colorless liquid with a pungent, choking odor (density 1.53g·cm-3 ) Concentrated nitric acid： 69% HNO3 by mass， (density 1.4g·cm-3 ). Pure HNO3 is colorless, but some acid decomposes during the preparation to give brown gas NO2 which colors the product. 4 Π 3 Structure： N：sp2 hybridization Π 6 Π 4 ? N: 2S22P3 ; O: 2S22P4
Chemical properties of HNO3 1 Powerful oxidizing agent HNO,+非金属单质→相应高价酸+NO 4HN03+3C→3C02(g)+4NO(g)+2H20 5HNO,+3P+2H,O->3H,PO+5NO(g) 2HNO3+S→HSO4+2NO 10HNO3+3L2→6HI03+10N0+2H20
Chemical properties of HNO3 ① Powerful oxidizing agent HNO3 +非金属单质 ⎯→相应高价酸+ N O 10HNO3 + 3I2 ⎯→6HIO3 +10NO+ 2H2 O 2HNO3 +S ⎯→H2 SO4 + 2NO 5HNO 3P 2H O 3H PO 5NO(g) 3 + + 2 ⎯→ 3 4 + 4HNO3 + 3C ⎯→3CO2 (g) + 4NO(g) + 2H2 O
Concentrated nitric acid will oxidize almost all metals,but the exact product depends on the metal (the reducing agent)and acid concentration. Cu+4HNO3(浓一Cu(NO3)2+2NO2+2H2O 3Cu+8HNO,(稀一3Cu(NO3)2+2NO+4H2O Au,Pt,Nb,Ta etc don't react with HNO; concentrated nitric acid Copper reacts with
Concentrated nitric acid will oxidize almost all metals, but the exact product depends on the metal (the reducing agent) and acid concentration. Cu + 4HNO3 (浓) Cu(NO3 )2 + 2NO2 + 2H2O 3Cu + 8HNO3 (稀) 3Cu(NO3 )2 + 2NO + 4H2O Copper reacts with concentrated nitric acid Au, Pt, Nb, Ta etc don’t react with HNO3