Page 33 - Curriculum Visions Dynamic Book

The U-tube for condensing the gas is partly immersed in an ice bath during the experiment.
 Any nitrogen dioxide not collected in the U tube dissolves in water to produce nitric acid. Oxygen gas (which,
in contrast to nitrogen gases, is not very soluble in water) can be collected in the inverted test tube.
 The brown fumes enter the U-tube, which is kept in an ice bath. Here you can see that the fumes are a mixture of gases. The tube has been taken out
of the ice bath temporarily for this picture. The brown fumes are nitrogen dioxide, NO2, one of the main smog gases. The green liquid that has condensed out as the nitrogen dioxide
is cooled contains N2O4, a yellow liquid which in this case is contaminated by a blue impurity, possibly N2O3.
 The condensed liquid
is poured into a flask and then immersed in hot water. Brown nitrogen dioxide fumes are given off.
EQUATION: Decomposition of lead nitrate
Lead nitrate ➪ lead oxide + nitrogen dioxide + oxygen 2Pb(NO3)2(s) ➪ 2PbO(s) + 4NO2(g) + O2(g)
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