Tests for Carbon Dioxide

Q.

Give reasons for the following:

Lime water turns milky when it comes in contact with air.

Q. Which of the following can be used to extinguish a fire caused by petrol?
1. Water
2. Sand
3. Carbon dioxide

1. 2 and 3
2. 1 and 3
3. 1, 2 and 3
4. 1 and 2

Q.

Define a chemical reaction.