Question

Name the brown coloured gas evolved when lead nitrate crystals are heated in a dry test tube

Answer 1

When lead nitrate is heated strongly, NO2 and O2 are given out.

2Pb(NO3)2 (s) ------> 2PbO (s)  +  4NO2(g)  +  O2 (g)

In this decomposition reaction, the colourless compound lead nitrate forms a yellow compound, lead monoxide, and brown fumes of nitrogen dioxide gas are evolved.

Since the decomposition of lead nitrate is brought about by heat, it is actually an example of thermal decomposition. 

Answer 2

Answer:

nitrogen dioxide gas

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