What are alloys? Name an important alloy which contains some of the lanthanoid metals. Mention its uses.

An alloy is a solid solution of two or more elements in a metallic matrix. It can either be a partial solid solution or a complete solid solution. Alloys are usually found to possess different physical properties than those of the component elements.

An important alloy of lanthanoids is Mischmetal. It contains lanthanoids $(94-95 \%),$ iron $(5 \%),$ and traces of $S, C, S i, C a,$ and $A I$ Uses

$(1)$ Mischmetal is used in cigarettes and gas lighters.

$(2)$ It is used in flame throwing tanks.

$(3)$ It is used in tracer bullets and shells.