Solder Is a Fusible Metal Alloy Used to Join Together

Solder is a fusible metal alloy used to join together metal wires or work pieces.Old-style solder was often 60% tin (r = 140 pm) and 40% lead (r = 154 pm) .Heating the solder caused it to melt; upon cooling,small sites would develop that were richer in Pb,which has a higher melting point than Sn.Cooled solder is best classified as ________

A) a homogeneous alloy.
B) a heterogeneous alloy.
C) an interstitial alloy.
D) a colloidal alloy.
E) an intermetallic compound.