Question

When the first element of the periodic table is treated with di-oxygen, it gives a compound whose solid state floats on its liquid state. This compound has an ability to act as an acid and a base. What products will be formed when this compound undergoes auto ionization?

Answer 1

The first element of periodic table is hydrogen and its molecular form is H₂. It reacts with oxygen to form water whose solid state is ice which is lighter than water and floats on it. Water is amphoteric in nature i.e., it acts as an acid in the presence of strong base and as a base in the presence of strong acid. 

As an acid : 

2H₂O(l) + NH₃(aq) → NH₄⁺(aq) + OH (aq)

As a base : 

2H₂O(l) + H₂S(aq) →  H₃O⁺ + HS- Due to amphoteric nature,

water undergoes self ionization as: 

H₂O + H₂O → H₂O⁺ + OH^-