Fill in the blanks:

(a) …………… is formed when charcoal is burnt in a limited supply of air.

(b) Coal is a …………… form of carbon.

(c) …………… is the most inferior form of coal.

(d) Wood charcoal is a …………… conductor of heat and electricity.

(e) …………… is used in making black shoe polish.

Anthracite is

1. an inferior type of coal
2. a superior type of coal
3. a cheapest form of coal
4. none of the above

Lamp black is

1. an amorphous form of carbon
2. a crystalline form of carbon
3. a pure form of carbon
4. a cluster of carbon atoms

The process by which decayed plants slowly convert into coal is called

1. petrification
2. carbonization
3. carbonification
4. fermentation