Question

. A 13 mL sample of a solution of AlBr3 was diluted with water to 56 mL. A 25 mL sample of the dilute solution was found to contain 2.21 M Br-. What was the concentration of AlBr3 in the original undiluted solution?

Answer 1

13 mL is diluted to 56 mL so everything in the original sample is now in 56 mL. If we take 25 mL of that and the M is 2.21M, the the amount in the 56 mL is 2.21M x (56 mL/25 mL) = ?

Answer 2

That's for Br^-. Divide by 3 for AlBr3.