2. Which of the following is correct about ozone?

[A] it is a red coloured gas
[B] it is odourless
[C] it is harmless in small concentrations
[D] All of the above

A 10.03 mL aqueous aliquot required 32.46 mL of 0.01078 M sodium thiosulfate (Na₂S₂O₃) to reach a colourless endpoint after addition of starch solution. In a separate titration, a 5.09 mL methylene chloride (CH₂Cl₂) aliquot used 18.51 mL of 0.01078 M thiosulfate to reach the endpoint.

a) Calculate the concentration of iodide in the aqueous layer.

b) Calculate the concentration of aqueous triiodide ion.

c) Calculate the concentration of aqueous iodide ion.