If 840 Ml Of 0 310 M Aqueous Hclo4 And 450 Ml Of 1 47 M Aqueous Ba Oh 2 Are Reac

If 840 mL of 0.310 M aqueous HClO4 and 450 mL of 1.47 M aqueous Ba(OH)2 are reacted stoichiometrically according to the balanced equation, how many milliliters of 1.47 M aqueous Ba(OH)2 remain? Round your answer to 3 significant figures.