21. Solving a chemistry problem

144. Calculate the concentration of hydrogen ions and pH of aqueous solutions without taking into account ionic strength.
a) 0.1 N HCl solution, the degree of dissociation of which is 91%
b) The solution was prepared by diluting 5 ml of 1N NH4OH solution with water to 50 ml.
c) The solution was obtained by mixing 50 ml of a 0.2 N solution of CH3COOH with 50 ml of a solution containing 0.82 g of CH3COONa