
Give the main experimental points only to demonstrate that Candle gains weight on burning.

Important Questions on Air & Atmosphere
Give reasons for the following: Patients suffering from lung problems are kept in an oxygen tent.

Give reasons for the following:
Oxygen finds utility in welding & cutting of metals.

Match the following.
List I | List II |
1. The constituent of air which is around . | A. Nitrogen |
2. The constituent of air which is inert or unreactive. | B. Oxygen |
3. The constituent of air which is non-combustible, but supports combustion. | C. Sulphur dioxide |
4. A pollutant in air responsible for acid rain. | D. Carbon dioxide |
5. The main rare gas present in air. | E. Argon |

Give reasons for the following:
Acid rain has caused damage to heritage structures such as the Taj Mahal.

Give reasons for the following:
In the laboratory preparation of oxygen from potassium chlorate - manganese dioxide is added to the reactant.

Give reasons for the following:
Oxygen gas does not affect moist blue litmus paper, but carbon dioxide turns it slightly pink.

Give reasons for the following:
Oxidation of sulphur results in a product which turns moist blue litmus red.

Give reasons for the following:
Combustion and respiration show similarity.
