Procedure 1. A 25 mL round bottom flask equipped with a stir baris loaded with 13 mg of CdO powder, 0.6 mL of oleic acid, and 10 mLof 1-octadecene. The reaction flask is placed into a heating mantleand surrounded with aluminum foil so that the temperature can reach225 °C, which will take approximately 1 hr. Some hot plates mayheat up faster and the experiment can be performed sooner. 2. Asthe CdO solution is heating, the Se solution should be prepared.Five students can share the Se solution, since only 1 mL isrequired for each reaction. A 25 mL round-bottom flask equippedwith a stir bar is loaded with 30 mg of Se and 5 mL of 1-octadeceneand allowed to stir at room temperature. To this stirred solutionwas added 0.4 mL of trioctylphosphine via syringe. The mixture willturn homogeneous. At this point it is ready for the next step. 3.Once the CdO solution has reached a temperature of about 225 °C,add 1 mL of the Se solution from step 2 in a rapid fashion. As soonas you add the Se solution start collecting samples ofapproximately 1 mL into separate test tubes continuously as thereaction will be changing colors from yellow to orange to bloodred. 4. After allowing the quantum dot solutions to cool, add 1 mLof pentane to the test tube containing ~1 mL of sample. Then,pipette the samples into a glass cuvette to record their UV-Visspectra. Use pentane as the blank. The solutions collected in testtubes can be stored overnight in the hood or drawer withoutdecomposition if there is not enough time to record UV-visspectra.

What reaction is occurring when the selenium dissolves aftertrioctylphosphine is added.