A few students of class XII were playing in the stadium under the supervision of their coach. All of a sudden, Nitin fell down. The coach immediately rushed towards Nitin and examined the injury. He opend up his sporting kit and pulled out a small plastic pack. He squeezed hard the pack and placed it on the injured portion of his skin. Nitin got some conform and relief. Later coach took Nitin to hospital for further treatment.
Read the above passage and answer the following questions :
(i) What values were expressed by coach towards Nitin ?
(ii) Name the chemical contained in the plastic pack. What is this pack called and how does it work ?
(iii) Name two other uses of the chemical contained in the small plastic pack.

Explanation

(i) The coach expressed the human values and helped Nitin who was in pain. He provided the first aid and took him to the hospital for further treatment.
(ii) The chemical contained in the small plastic pack is ammonium nitrate and the small pack is called the instant cold pack. An instant cold plastic pack has two compartments , one contains solid ammonium nitrate `(NH_(4)NO_(3))` and the other contains water. When the plastic pack is squeezed hard, the wall between the two compartment breaks. The `NH_(4)NO_(3)` mixes with water, endothermic reaction occurs and the temperature drops. The cold pack is then placed on the injured tissues. It takes out the heat from the injured tissues, reduces swelling and bleeding by decreasing the capillary size of the blood vessels under the bruised skin. As a result, the person gets relief from the pain.
(iii) Ammonium nitrate is a useful fertilizer because plants usually take up nitrogen in the form of nitrate and ammonium ions. Ammonium nitrate mixed with fuel oil is one of the most deadly explosives used for coal mining and demolition of buildings. During explosion, oxidation-reduction reaction occurs , `NH_(4)^(+)` ion is the reducing agent while `NO_(3)^(-)` ion is the oxidising agent. As a result, fuel oil `(C_(17)H_(36))` gets oxidized and a large volume of gases is produced which causes explosion :
`52 NH_(4)NO_(3)(s) + C_(17)H_(36)(l) rarr 52 N_(2)(g) + 17 CO_(2)(g) + 122 H_(2)O(g)`
But unfortunately, in the recent years, this explosive has been used in terrorist attacks in India and around the world.