Question

copper is mixed with gold to make ornaments because alloying

Answer 1

Pure gold is very soft and it is not used for making jewellery. Copper or silver is added to pure gold to make it hard. Pure gold is called 24 carat gold. This is alloyed with silver or copper to make it hard.

Answer 2

because gold in its pure state i.e. 24 crt found in the form of power when it is alloyed with copper it converts into hart metal