Question

(a) How does the painting of an iron object prevent its rusting ?

(b) How does the electrical conductivity of copper alloys, brass and bronze, differ from that of pure copper ?

(c) What is meant by 22 carat gold ? Name the metals which are usually alloyed with gold to make it harder

Answer 1

(a) When a coat of paint is applied to the surface of an iron object, it prevents air and moisture to come in contact with the object; hence no rusting takes place.

(b) The electrical conductivity of copper alloys like brass and bronze is less than that of pure copper.

(c) It means that 22 parts pure gold is alloyed with 2 parts of either silver or copper for making ornaments; Silver and copper are usually alloyed with gold to make it harder .