1. At equilibrium, it was found that [CH3COOH] = 0.8537 M, [CH3COOO-] = 0.0040 M and [H3O+] = 0.0040 M. Calculate the acidity constant of CH3COOH and the pH value of the solution.
2. Calculate the concentration of the hydronium ion ([H3O+]) for a solution with the pH = 4.5