Answer:
Option b = H2O + H2O <==> H3O+ + OH–
Explanation:
Dissociation of water:
The water molecule dissociate into the hydroxyl ion and hydrogen ion. The hydrogen ion immediately protonate the other water molecule and form the hydronium ion.
Chemical equation:
H2O + H2O <==> H3O+ + OH–
The equilibrium constant of self ionization of water is given below:
Kw= [H3O+][OH-]
[H3O+] is the concentration of hydronium ion while [OH-] is the concentration of hydroxyl ion.
Kw is called ionic product of water. The value of Kw is 1.0 × 10∧-14 at 25 °C.
The pure water consist of equal concentration of hydroxyl and hydrogen ions. In order to determine the molarity of both ions square root of ionic product (Kw) is taken.
[OH-]=[H+]= 1.0 × 10∧-7 M
In case of acidic solution concentration f hydrogen ions are greater than hydroxide ions. For example,
HCl when dissociate into water gives H+ and Cl-. The H+ ions increases in solution. The equilibrium is this given by water.
H2O ⇆ H+ + OH-
Reaction is forced to wards left. As a result concentration of hydroxide ions decreases.
In case of base solution like KOH when dissociate it gives K+ and OH -. The concentration of hydroxyl ions increases in this case and concentration of H+ is decreases and ionic product remain constant.
