A1. First it is important to know that nitric acid (HNO3) is a strong acid and so [HNO3] = [H+] Beaker A contains 100cm^3 = 100ml Final volume is 150ml (50cm^3 of distilled water is added to beaker A) So, (100ml/150ml) x 0.0125 mol/dm^3 will give a [H+] as 8.3 x 10^-3 as pH = -log[H+], pH = 2.08