Grade 12th PassInorganic Chemistry

Is water the strongst electrolyte among diluted solvents?

Mohammed Razik

14 Years agoGrade 12th Pass

1 Answer

ruchi yadav

12 Years ago

Water is a very weak electrolyte. The ionization orautoionizationof pure water can be represented by the ionization equation,

H₂O = H⁺+ OH^-and the equilibrium constant is,

      [H⁺] [OH^-]
  K = -----------
        [H₂O]

For pure water, [H₂O] is a constant (1000/18 = 55.6 M), and we often use theion product,K_w, for water,

K_w=K[H₂O] [H⁺] [OH^-]

The constantK_wdepends on temperature. At 298 K,K_w= 1x10^-14. If there is no solute in water, the solution has equal concentrations of [H⁺] and [OH^-].

[H⁺] = [OH^-] = 1x10^-7,andpH = - log [H⁺]= 7.

Note that only at 298 K is the pH of water = 7. At higher temperatures, pH is slightly less than 7, and at lower temperature, the pH is greater than 7.