Complete the crossword Fig. 6.1 with the help of the clues:

Across

1. Non-metal which catches fire if exposed to air (10) oxygen to give off heat. (10)

3. The lowest temperature at which a substance catches fire is called its __________temperature. (8)

5. The most common fire extinguisher. (5)

Down

2. A chemical process in which a substance reacts with

4. Petrol is used as a __________ in automobiles. (4)

6. It is as hard as stone and black in color. (4)