Question

If 486mL of 0.85M HCl solution is neutralized with 335mL of Sr(OH)2 solution, what is the molarity in M of Sr(OH)2?

Answer 1

because \(Sr(OH)_2\) makes two \(OH^-\) per molecule, it's twice as strong. as HCl.

you can see this with the balanced reaction: \(Sr(OH)_2 +2HCl\rightarrow H_2O +SrCl_2\) to counteract the effect of 1 molecule of \(Sr(OH)_2\) you needed 2 HCl molecules.

So you can do this the long way (find moles, then find equivalent moles, then convert back to molarity) or you can use \(M_1V_1=M_2V_2\) if you take the fact that it's twice as strong into account.