题目

NO和NO2具有下列不同性质：(1)通常情况下，NO是无色气体，难溶于水；NO2是红棕色气体，易溶于水；(2)NO2与水反应为3NO2+H2O＝2HNO3+NO。如图，将一支充满NO2气体的试管倒立在烧杯中，试分析反应完全后可能出现的实验现象                                                                               。_______ he did well, he was never top of his class.A．Although B．ButC．Because D．Since