[Hoodat]

How did you standardize the acid solutions (i.e. how do you know what their molarities are)?

[BenKenobi]

There’s 4 variables.

Concentration X, Concentration Y, Crystal Z and Crystal W

Adding concentration X to Z and W gives me two equations:

X+Z -> XZ
X+W -> XW

Adding concentration Y to Z and W gives me two more equations:

Y+Z -> YZ
Y+W -> YW.

I can then use the systems of equations to solve for all 4 variables, once I know the concentration of acid required to dissolve YW and YW. To keep it easier, I make sure I have the exact same amount of both Z and W, and I keep the concentration in the standard solution the same. The only thing that will change between the two is the volume of the acid.