Question

A brown substance 'X' on heating in air forms a compound 'Y'. When hydrogen gas is passed over 'Y', it changes to 'X' again. (i) Name the substances 'X' and 'Y'. (ii) Name the processes occuring during the two changes.

Answer 1

x is copper
y is copper oxide

Cu +O2→2CuO
CuO+H2→Cu+H2