88. Solving a chemistry problem

6. Calculate the pH of the following solutions:
a) The solution was obtained by diluting 20 ml of 10% sulfuric acid solution (density 1.067 g/cm3) with water to 400 ml.
b) Solution, 100 ml of which contains 0.6 g of acetic acid.
c) The solution was obtained by mixing 100 ml of 0.2 N ammonia solution with 200 ml of 0.1 N ammonium chloride solution.