Write a note on Alloys.

ANS : An alloy is a homogeneous solid solution of two or more metals or a metal and a nonmetal. An alloy is generally prepared by heating the mixture of its constituents to molten state and then cooling it at room temperature. An alloy is prepared to obtain material with desired properties because the properties of constituents of an alloy are modified to some extent. Sometimes the melting point of an alloy is lower than that of the constituents. For example, solder is an alloy of lead and tin. Its melting point is lower than that of lead and tin and it is used in soldering of electrical wires.

Pure gold cannot be used to make jewellery as it is very soft. To make it hard, it is generally alloyed with copper or silver. The purity of gold is expressed in CARATS. Pure gold is 24 carats. 18 carat gold means it contains 18 parts of gold in 24 parts by weight of the alloy.