一、考查硝酸的不稳定性知识要点:硝酸见光、受热易分解,硝酸的浓度越大越易分解.知识运用:由于分解产生的NO_2能溶于硝酸溶液中,故久置的浓硝酸往往呈黄色,这也说明了4HNO_3=4 NO_2↑+O_2↑+2H_2O这一反应的可逆性.由这一反应也可推出硝酸的不稳定性,推出HNO_3的制备和相关的实验一般不在较高的温度下进行,推出HNO_3一般要保存在棕色的试剂中,且置于阴凉处. First, examine the instability of nitric acid knowledge points: nitric acid see light, heat easily decomposed, the greater the concentration of nitric acid easier decomposition. Knowledge use: As the decomposition of NO2 can be dissolved in nitric acid solution, so long home concentrated nitric acid is often presented Yellow, which also shows the reversibility of 4HNO_3 = 4 NO2↑ + O2↑ + 2H_2O this reaction can also be introduced by the reaction of nitric acid instability, the introduction of HNO_3 preparation and related experiments are generally not at a higher temperature Below, the introduction of HNO_3 is generally stored in a brown reagent and placed in a cool place.