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JEE Main 2026 Preparation: Question Papers, Solutions, Mock Tests & Strategy Unacademy » JEE Study Material » Chemistry » K2Cr2O7 Potassium Dichromate

K2Cr2O7 Potassium Dichromate

otassium dichromate is a chemical substance that has a lot of industrial and laboratory applications. It has the chemical formula K2Cr2O7 and is an orange crystalline solid. It is a strong oxidizing agent that is water soluble.

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Potassium compounds are prevalent and helpful for a wide range of applications. For ages, potash and other potassium compounds have been employed in the production of glass. Today, fertilizers are made from 95 percent of the potassium compounds collected around the world.

Potassium dichromate is a chemical substance that has a lot of industrial and laboratory applications. It has the chemical formula K2Cr2O7 and is an orange crystalline solid. It is a strong oxidizing agent that is water soluble. For the preparation of chrome alum, chrome yellow, and chrome red, it is employed in the volumetric measurement of ferrous salts, iodides, and sulfides.

What is potassium dichromate (K2Cr2O7) and what does it do?

Potassium dichromate, also known as K2Cr2O7, is an inorganic chemical reagent. Potassium bichromate, or Potassium bichromate, is another name for it. It has a vivid red-orange color and is a crystalline ionic solid. It has no odor and is insoluble in acetone and alcohol, but it dissolves in water.

It’s a common ingredient in potassium chrome alum and leather tanning. It’s widely used as an oxidizer in a variety of industries and laboratories. It’s extremely corrosive and non-flammable. 

The following steps are used to make potassium dichromate:

  1. By combining potassium chloride with sodium dichromate or by combining sodium dichromate with potassium chloride
  2. Produced by burning chromite ore with potassium hydroxide to produce potassium chromate.
  3. Potassium dichromate – K2Cr2O7 – Properties
  4. Potassium dichromate (K2Cr2O7)
  5. Molar Mass/Molecular Weight 294.185 g/mol
  6. 2.68 g/cm3 density
  7. Temperature at which water boils is 500 degrees Celsius.
  8. 398 °C melting point

The following are some of the most important features of potassium dichromate.

  • K2Cr2O7 has a reddish-orange crystalline look.
  • At 0°C, the solubility of this chemical in water is 49 grams per liter.
  • Alcohol and acetone are insoluble in this combination.
  • K2Cr2O7 has a heat capacity of 219 Joules per mole.
  • This compound’s standard molar entropy is 291.2 joules per kelvin mole.

Structure of potassium dichromate (K2Cr2O7 Structure)

Potassium The two positively charged potassium cations and the dichromate anion, which has a charge of -2, form two ionic bonds in dichromate molecules. Two chromium atoms are linked to four distinct oxygen atoms in the dichromate ion. Two of the Cr-O links are double bonds, with one oxygen atom connected to both chromium atoms. The charge of the last oxygen atoms individually linked to the chromium atom K2Cr2O7 is potassium dichromate.

Uses of potassium dichromate (K2Cr2O7)

  • In cement, it is used to delay the setting of the mixture and to improve the density and texture.
  • In photographic screen printing, it’s used.
  • It’s a typical reagent in analytical chemistry that’s used for traditional “wet tests.”
  • It’s used to create deep, rich browns in specific types of wood.
  • It is used to clean glassware as well as as an etching medium.
  • Along with iron and tungsten, it’s used in pyrotechnic displays.
  • It can be used as an antiseptic, caustic, and astringent externally in medicine.

When potassium dichromate is dissolved in a 35 percent nitric acid solution, it produces Schwerter’s solution, which is an analytical reagent. This reagent can be used to check for the presence of various metals, particularly silver purity. The solution is reported to turn bright red when made using pure silver, but dark red when made with sterling silver. Furthermore, the use of low-quality coin silver causes the solution to turn brown (mainly because of the presence of copper that turns the solution brown). Schwerter’s solution would also turn green if 0.500 silver was added. Brass turns this solution dark brown, whilst copper imparts a brown color, despite the fact that gold and palladium do not move. Finally, when the metals lead and tin are added to a solution of potassium dichromate in 35 percent (approx.) nitric acid, they produce yellow solutions.

Conclusion

Potassium dichromate has a strong effect on the respiratory tract, causing ulcers. K2Cr2O7 is a recognised human carcinogen that has been linked to an increased risk of lung cancer.

Accidental intake of the material can create toxic effects; animal investigations suggest that ingestion of less than 40 grams can be fatal or severely affect an individual’s health.The substance can cause chemical burns in the oral cavity and gastrointestinal tract after intake.Acute potassium poisoning is uncommon after ingestion since vomiting usually ensues and renal excretion is quick.Potassium causes a sluggish, weak pulse, abnormal cardiac rhythms, heart block, and a reduction in blood pressure.

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Frequently Asked Questions

Get answers to the most common queries related to the JEE Examination Preparation.

What happens if potassium dichromate is present?

Ans. Potassium dichromate is a milder oxidizing agent than potassium pe...Read full

Is potassium dichromate water soluble?

Ans. The acidification of potassium chromate produced this brilliant o...Read full

What is the purpose of potassium dichromate?

Ans. Potassium dichromate, K2...Read full

Is potassium dichromate a pure form of the metal?

Ans. The two chemicals, potassium dichromate and water, are mixed toget...Read full

What is the significance of the color of potassium dichromate?

Ans. The crystal of potassium dichromate is vivid red-orange in color. ...Read full

Ans.

Potassium dichromate is a milder oxidizing agent than potassium permanganate in organic chemistry. It’s employed in the oxidation of alcohol. Under more strong conditions, it converts primary alcohols to aldehydes and carboxylic acids.

Ans.

The acidification of potassium chromate produced this brilliant orange crystal. Potassium bichromate, or potassium dichromate, is another name for potassium bichromate. It’s toxic and oxidizing, and it’s soluble in water but not in alcohol.

 

Ans.

Potassium dichromate, K2Cr2O7, is a common inorganic chemical reagent used as an oxidizing agent in a variety of laboratory and industrial applications. As with all hexavalent chromium compounds, it is both immediately and chronically harmful to fitness.

Ans.

The two chemicals, potassium dichromate and water, are mixed together. Every portion of the sample is equivalent to any other portion of the sample because potassium dichromate is uniformly dissolved in the bath. It is true that the combination is homogeneous. It is a pure substance because it is a single chemical compound.

Ans.

The crystal of potassium dichromate is vivid red-orange in color. The complex’s hue is due to a d-d transition, in which oxygen transfers an electron to the Cr6+ complex’s unoccupied d- orbital. The charge transfer from ligand to metal is known as ligand to metal charge transfer (LMCT). As a result of this electrical transition, light is absorbed and the complementary color is visible.

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