Properties of Potassium Dichromate
Potassium Dichromate has a variety of properties which are classified into physical and chemical properties. The physical and chemical properties of Potassium Dichromate are described below:
Physical Properties of Potassium Dichromate
The physical properties of Potassium Dichromate are Tabulated below:
Physical Properties of K2Cr2O7 |
|
---|---|
State |
Crystalline Ionic Solid |
Colour |
Bright Red-Orange |
Odor |
odorless |
Solubility |
Soluble in water, Insoluble in Acetones and Alcohol |
Refractive index |
1.738 |
Boiling Point |
500° Celsius |
Melting Point |
398° Celsius |
Density |
2.68 grams per cubic centimeter |
Molecular weight |
294.185 g/mol |
Nature |
non-combustible but highly corrosive |
Chemical Properties of Potassium Dichromate
The chemical Properties of K2Cr2O7 can be best understood in the terms of chemical reaction it undergoes. Hence, the chemical reactions of Potassium Dichromate are mentioned below:
Reaction due to Heat
On heating, Potassium Dichromate decomposes to give out potassium chromate with the evolution of oxygen (O2) gas. The chemical reaction involved is as follows:
4 K2Cr2O7 → 4K2CrO4 + 2Cr2O3 + 3O2
Oxidation Reaction
Being an oxidizing agent, each mole of potassium dichromate liberates three atoms of oxygen when reacted with dilute H2SO4, this reaction is illustrated below:
K2Cr2O7 + 4H2SO4 → K2SO4 + Cr2 (SO4)3+ 4H2O + 3(O)
Reaction with Alkalies
When Potassium Dichromate reacts with alkalies, potassium chromate is formed due to which the orange-red colour of K2Cr2O7 changes into a yellow colour. It is represented by the following chemical reaction:
K2Cr2O7 + 2KOH → 2K2CrO4 + H2O
This yellow-coloured potassium chromate changes back to orange-red coloured potassium dichromate when acidified. The reaction involved here is:
2K2CrO4 + H2SO4 → K2Cr2O7 + K2SO4 + H2O
This process of conversion of potassium dichromate into potassium chromate and then conversion of potassium chromate back to potassium dichromate is due to equilibrium between Cr2O72- ions and CrO42- ions.
Cr2O72- + H2O ⇋ 2CrO42- + 2H+
Acidified Potassium Dichromate
Potassium dichromate solution can be acidified by adding dilute sulphuric acid along with a few drops of the aldehyde or ketone. Acidified Potassium Dichromate can produce sulphur, potassium sulphate, chromium(III) sulphate, and water on reaction with hydrogen sulphide. On reaction with SO2 the orange solution of acidified Potassium Dichromate turns green due to the formation of a green colour compound Cr2(SO4)3.
Potassium Dichromate (K2Cr2O7)
Potassium Dichromate is a chemical compound mainly used as an oxidizing agent. The chemical formula of Potassium Dichromate is represented as K2Cr2O7. It is a hexavalent chromium compound having a bright red-orange color. It serves as an oxidizing agent in various industrial and laboratory applications. It is used to manufacture products such as matches, glass, ceramics, etc.
In this article, we will thoroughly study What is Potassium Dichromate, its structure, its preparation, and its wide range of applications.
Table of Content
- What is Potassium Dichromate?
- Formula of Potassium Dichromate
- Structure of Potassium Dichromate
- Molecular Weight of Potassium Dichromate
- Preparation of Potassium Dichromate
- Properties of Potassium Dichromate
Contact Us