Question

(Redox) Titration Problem

Testing for the concentration of ozone dissolved in water can be accomplished by titrating a known volume of the solution to be tested a with standardized potassium bromide solution. The reaction that takes place forms oxygen gas and the bromate ion which can be detected spectroscopically. In a particular experiment, a 25.00 mL ozone containing solution was titrated with 37.41 mL of 0.3290 M potassium bromide. Determine the concentration of ozone in the original solution.

*Please show detailed work so I can figure out how to do the problem. Thank you for your time

Answer 1

Ans. #Step 1: Given- vol. of KBr soln. consumed = 37.41 mL = 0.03741 L

Moles of KBr consumed = Molarity x Vol. in liters

                                                            = 0.3290 M x 0.03741 L = 0.01230789 mol

# Step 2: Balanced reaction:           2 O₃ + 2 KBr ------> K2 + 2 BrO₃

Following stoichiometry of balanced reaction, 2 mol O3 is neutralized by 1 mol KBr. So, the moles of O₃ in the solution must be equal to the moles of KBr consumed to reach the end point.

Hence, moles of O₃ in solution = 0.01230789 mol

# Given- Vol. of original test solution = 25.00 mL = 0.025 L

Now,

            [O₃] in original solution = Moles / Vol. in liters

                                                = 0.01230789 mol / 0.025 L = 0.4923 M = 0.50 M