Question

(a) write the chemical name of the coating that forms on silver and copper articles when these are left exposed to moist air. (b) explain what is galvanisation. What purpose is served by it? (c) define an alloy. How are alloys prepared? How do the properties of iron change when: (1) small quantity of carbon, (2) nickel and chromium are mixed with it.

Answer 1

a) Ag₂O

CuO

b) Galvanization means coating of Zinc on Iron articles to prevent it's corrosion.

c) Alloy is mixture of 2 or more metals, they have high metling point and are more resistable than the sole elements

1) Iron becomes hard and it's strength increases.

2)Stainless steel is formed and it never corrodes.