Mix 0.1L of 0.1mol/L H2SO4 with 0.3L of distilled water. Calculate concentration of H2SO4 and pH of solution

0.1L of 0.1mol/L H2SO4 mixed with 0.3L of distilled water, dilutes it to 0.4 litres:

(0.1mol/L H2SO4) ( 0.1 L diluted) / (up to 0.4 L) = 0.025 Molar H2SO4


with only a 1 sig fig problem...
the strong acid, 0.025 Molar H2SO4 releases twice as many H+ ions = 0.050 Molar

the pH of 0.05 Molar H+ = - log of [0.050]
pH = 1.3