化学实验中的很多气体是用盐酸来制取的，这就导致了这些制取的气体中往往含有HCl杂质，要除去HCl杂质而得到纯净的目标气体，可用右图所示装置。如果广口瓶中盛装的是饱和NaHCO3溶液，则可以用于下列哪种气体的除杂装置是 （ ）。
A．H2
B．Cl2
C．H2S
D．CO2
答案：D
用化学的方法除去杂质时，不能再引入新的杂质，也不能与要制的物质反应，这是除杂的基本原则。
盐酸是一种挥发性的强酸，使用盐酸制取气体时往往含有
杂质.将氢气和的混合气体通过饱和NaHCO3溶液，可以除去其中的杂质，但同时又产生的新的杂质
，投制得的氢气依然不纯，其反应方程式为：
，不合要求；
制
时，将与
反应，损失掉大量的，同时也会有新的杂质产生，也不合要求.
制
时，将与反应，损失掉大量的，同时也会有新的杂质产生，也不合要求.
当制取的是时，混合气体通过时，发生的反应恰好产生的是，既除去了杂质，也没有产生新的杂质，符合要求.
故正确答案为D
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