Determining Molarity of strong acid [ENDORSED]

[RJ Lopez 2l]

Determine the initial molar is of Ba(OH)2 in an aqueous solution that contains 0.43 g of Ba(OH)2 in 0.100 L solution

Calculate the molarities of Ba2+, OH-, and H3O+ in the same solution

I figure our the molarity of BA2+ (0.025] and OH- (0.050M) but how would we determine the H3O+ if there is none present in the reaction?

[Ethan Cheng 2k]

I think you would have to find the pOH using the concentration of OH-, then find the pH, which is just 14-pOH, and use the pH to find the concentration of H3O+, which is 10^(-pH).