Question

What is the action of heat on ${{K}_{2}}C{{r}_{2}}{{O}_{7}}$ ?

Answer 1

We know that ${{K}_{2}}C{{r}_{2}}{{O}_{7}}$ is called Potassium dichromate, it is important inorganic chemical reagent, which as is an oxidizing agent and used in laboratory. It is found to have various industrial applications and is chronically harmful to health.
It is a crystalline ionic solid which is very bright, and has a red-orange colour. On action with heat, oxygen gas is liberated.

Complete answer:
- We can see that ${{K}_{2}}C{{r}_{2}}{{O}_{7}}$ is potassium dichromate, which is economically an important reagent.
- When it is heated strongly, it decomposes to give the products.
- We can see from the following reaction that the decomposition takes place:
$4{{K}_{2}}C{{r}_{2}}{{O}_{7}}\to 4{{K}_{2}}Cr{{O}_{4}}+2C{{r}_{2}}{{O}_{3}}+3{{O}_{2}}$
- Here, we can see that the evolution of oxygen gas takes place.
- With the evolution of oxygen gas, potassium chromate and chromium oxide are also formed.
- Potassium chromate is the inorganic compound with the formula ${{K}_{2}}C{r}{{O}_{4}}$. This is actually a yellow solid which is the potassium salt of the chromate anion.
- Chromium(III) oxide is also called as chromia , which is an inorganic compound with the formula $C{{r}_{2}}{{O}_{3}}$ .It is found that it is one of the principal oxides of chromium and is used as a pigment. In nature, it occurs as the rare mineral that is called eskolaite.

Additional information:
- It is found that the Dichromate colloids were also used as photoresists in various industrial applications, mostly in the creation of metal printing plates for use in various photomechanical printing processes.
- The Cr(VI) compounds are found to have the property of tanning animal proteins when exposed to strong light, and this quality is used in the photographic screen-printing process.

Note: - We can note here that important compounds like ${{K}_{2}}C{r}{{O}_{4}}$ and $C{{r}_{2}}{{O}_{3}}$ are produced. And oxygen gas is also liberated. While writing the reaction we must not forget to balance the reaction.