Question

"If the iodide-starch indicator paper changes to a blue-black color, proceed to the quench step. If the paper remains colorless (oxidizing agent not present), what can be done to ensure the agent is present?"

a. Increase the temperature
b. Add more cyclohexanol
c. Add more hypochlorite
d. Repeat the experiment

Answer 1

If the iodide-starch indicator paper remains colorless, adding more hypochlorite can ensure the presence of an oxidizing agent necessary for the desired color change.

Step-by-step explanation:

When using iodide-starch indicator paper, a blue-black color change indicates the presence of an oxidizing agent due to the formation of a starch-I3 complex.

If no color change is observed, implying that the oxidizing agent is not present, one could consider adding more hypochlorite to the reaction mixture, as hypochlorite is an oxidizing agent that could potentially drive the oxidation of iodide to iodine, which then forms the blue-black complex with starch.

It is also important to note that precautions such as wearing goggles when performing chemical reactions are essential for safety in the laboratory.