1) Given aqueous solutions of 0.1 M weak acetic acid (CH3COOH , pKa = 4.72) and 0.1 M so- dium acetate ( NaC2 H3O2 ), calculate the volumes of acid and acetate to be mixed, in order to make 50 mL of a buffer solution with a pH = 5.2.

2) Given 0.1-M aqueous solutions of ammonium chloride (NH4Cl) and ammonia (NH3) to the so- lution of that weak base. Calculate the volumes of salt and ammonia to be mixed, in order to make 50 mL of a buffer solution with pH = 9.0. The ammonium ion (NH4+) has a dissociation constant of value Ka = 5.62.10^-10