Hello.
Last month, I was taking a selective test in which there was a question involving titration. The question itself is very common. It said that, in order to discover the concetration of a 10 mL solution of Mg(OH)2, the mixture was titrated with 12.5 mL of a HCl solution 0,5 mol/L. Then, it required the concentration of the solution of Mg(OH)2. However, I became very confused due to this specific excerpt of the problem: "The concentration of a sample of 10 mL of Mg(OH)2 that was titrated with 12,5 mL..." Well, maybe I'm too caught up in details, but I noticed that they'd used a restrictive clause in there, as if they wanted to know the concentration of Mg(OH)2 AFTER the titration. Well, the difference is that, in my accounts, instead of using 10 mL as the volume, I used 22.5 mL (10 mL + 12.5 mL of the HCl solution). That led me to the wrong answer, as I should've used 10 mL, apparently, as the volume.
Well, now I don't really know if it was their error or carelessness or if, because the mixtures react with each other, the volume really doesn't change at all. I mean, both of the solutions have water in them, they're not only HCl and Mg(OH)2, so I don't see how the volume won't change, especially in those low concentrations of solutes. I'd like to know, then, if it was my mistake and if there is any way to determine the final volume of the mixture of titrant + titrate in order to determine the final concentration in the mixed samples of one of the components.
Thanks in advance