Answer
(a) diagram
Work Step by Step
The ionic reaction of stoichiometric amounts of barium
hydroxide and hydrochloric acid is: Ba(OH)₂(aq)+2HCl→H₂O(l)+Ba²⁺(aq)+2Cl⁻
This means that the solution must contain free barium ions and chloride ions in a molar ratio of 1:2 respectively, which is best described in diagram (a).