Calculating Volume of HBrO4 Needs to Titrate LiOH, NaOH, and RbOH

November 5th, 2008

Free Chemistry Tutor Homework help

How many milliliters of 0.861 M HBrO4 are needed to titrate each of the following solutions to equivalence point?

75.0 mL of 1.46 M LiOH
48.1 mL of 1.55 M NaOH
281.0 mL of a solution that contains 44.2 g of RbOH per liter

Answer

For titration problem, there is a formula that you can use to solve titration problem. This formula is uneversal for all kind of titration, and the formula is:

V x N (acid) = V x N (base)

V is the volume and N is the normality. For the problem above we need to calculate the normality of all the solution. Just for remember, to change from molarity into normality for acid or base you just multiply the molarity with the number of proton (acid) or the number of OH- for base.

0.861 M HBrO4 = 0.861 N HBrO4

1.46 M LiOH = 1.46 N LiOH

1.55 M NaOH = 1.55 N NaOH

Normality of 281.0 mL of a solution that contains 44.2 g of RbOH are:

mole = 44.2 / 102.48 = 0.431 mol

M = 0.431 mol/0.281 L = 1.53 M = 1.53 N

1. 75.0 mL of 1.46 N LiOH

75.0 x 1.46 N = 0.861 N x V
V = 127,2 mL

2. 48.1 mL of 1.55 N NaOH

48.1 x 1.55 N = 0.861 N x V
V = 86.6 mL

3. 281.0 mL of 1.53 N RbOH

281.0 x 1.53 N = 0.861 N x V
V = 499.3 mL