text: The hydration reaction of sulfuric acid is highly exothermic, dilution.
  As indicated by its acid dissociation constant, sulfuric acid is a strong acid:
  : K = 1000 (pK = −3)
  The product of this ionization is , the bisulfate anion.  Bisulfate is a far weaker acid:
  : K = 0.01 (pK = 2) 
  The product of this second dissociation is , the sulfate anion.