If 25.0 mL of 0.100 M #HCl# is titrated with 0.150 M #Ba(OH)_2#. what volume of barium hydroxide is required to neutralize the acid?

1 Answer
Jan 19, 2017

A little less than half the volume of the starting hydrochloric acid.

Explanation:

We need (i) a stoichiometric equation:

#Ba(OH)_2(aq) + 2HCl(aq) rarr BaCl_2(aq) + 2H_2O#,

Which shows us that 2 equiv acid react with the 1 equiv of barium hydroxide.

And (ii) we need the equivalent quantities of acid and base, observing the stoichiometry.

#"Moles of hydrochloric acid"# #=# #25.00xx10^-3*Lxx0.100*mol*L^-1=2.50xx10^-3*mol#

Given the stoichiometry, this molar quantity represents HALF of the molar quantity of barium hydroxide, which of course had an initial concentration of #0.150*mol*L^-1#. So we take the quotient,

#1/2xx(2.50xx10^-3*mol)/(0.150*mol*L^-1)xx10^3*mL*L^-1~=8*mL#

I have not checked the solubility of the barium salt. Barium hydroxide has limited aqueous solubility. Presumably this question is consistent with experiment.