Name two non-metals which are both brittle and non-ductile.

30 Name a non-metal having a very high melting point. 31 Which property of graphite is utilized in making electrodes ? 33 Explain why, the surface of some of some metals acquires a dull appearance when exposed to air for a long time. 34 Complete and balance the following equations:

(a)

(b)

(c)

(d)