A 250mL sample of a monoprotic acid solution has a pH of 2.60. Assuming the density of the solution is 1.00gmL−1 and that hydronium ions have a molar mass of 19.0gmol−1, what is the mass of hydronium ions present in the entire sample?
a) 1.2×102mg
b) 1.2mg
c) 1.2×101mg
d) 6.3×10−1mg