Question

What is the action of acidified potassium dichromate on the $KI$.

Answer 1

Hint: We know that potassium dichromate is an inorganic chemical reagent. We can use it as an oxidizing agent in industrial as well as laboratorial applications. It is an ionic compound that is crystalline in nature, and appears in red-orange colour. We can use potassium dichromate in the oxidation of alcohols.

Complete answer:
We can prepare potassium dichromate using potassium chloride on sodium chloride. Roasting chromite ore with potassium hydroxide also forms potassium dichromate.
The chemical formula of potassium dichromate is ${K_2}C{r_2}{O_7}$. It reacts with potassium iodide and forms iodine gas.
When acidified potassium dichromate reacts with potassium iodide, the products formed as potassium sulfate, chromium (III) sulfate, water, and iodine gas are liberated. It is an oxidation reaction and potassium iodide is oxidized to iodine in the presence of acidified potassium dichromate. There would be change in the colour of the solution to brown because iodine gas is liberated. We can write the chemical reaction as,
${K_2}C{r_2}{O_7} + 6KI + 7{H_2}S{O_4} \to 4{K_2}S{O_4} + C{r_2}{\left( {S{O_4}} \right)_3} + 7{H_2}O + 3{I_2}$

Note:
We can use potassium dichromate as,
-Potassium dichromate used in organic chemistry as an oxidizing agent.
-Precursor to potassium chrome alum, used in tanning of leather.
-It is used to prepare chromic acid for cleaning glassware and materials for etching.
-Due to its non-hygroscopic nature, we can use potassium dichromate as reagent for wet-tests in analytical chemistry.
-We can use potassium dichromate for testing sulfur dioxide.
-We can use potassium dichromate as an ingredient in cement.
-We can also use potassium dichromate in the oxidation of alcohols to give aldehydes, and carboxylic acids.