Question

Give reasons for the following: a) All thermal decomposition reactions are not thermal dissociations. b) Formation of NO from N2 and O2 can take place only at very high temperatures.

Answer 1

Answer:

Explanation:

a) It is a reversible reaction in which a substance dissociates (splits) into two or more simpler substances on application of heat.

b) Nitrogen  

Nitrogen has five valence electrons, so it needs three more valence electrons to complete its octet. A nitrogen atom can fill its octet by sharing three electrons with another nitrogen atom, forming three covalent bonds, a so-called triple bond. The triple bond formation of nitrogen is shown in the following figure.  

Oxygen  

Oxygen is commonly formed from water during photosynthesis, using the energy of sunlight. It is also produced in the troposphere by the photolysis of ozone by light of short wavelength, and by the immune system as a source of active oxygen.