Tue September 10, 2013 By: Nisha

9. A brown substance ‘X’ on heating in air forms a substance ‘Y’. When hydrogen gas is passed over heated ‘Y’, it again changes back into ‘X’. (i) Name the substance ‘X’ and ‘Y’ (ii) Name the chemical processes occurring during both the changes. (iii) Write the chemical equations involved in both the changes.

Expert Reply
Tue September 10, 2013

i) X and Y  is copper and Copper oxide

iii)Cu (brown substance,  X, Copper) + O2 = CuO (Y , black)Copper oxide)


CuO + H2  = Cu + H2O

ii)CuO undergo reduction and H2 goes oxidation so, it is redox reaction.
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