Chemistry, asked by davidLupho, 1 year ago

Preparation of potasium dichromate and potasium permanganate​

Answers

Answered by Avni2007
1
Preparation of Potassium Dichromate – K2Cr2O7

Potassium dichromate is an important chemical used in industries as an oxidizing agent and for the preparation of many other compounds.

Dichromates are usually prepared from chromates and this is obtained by the combination of chromite ore with sodium/potassium carbonate in the presence of air.

Potassium Dichromate

Potassium Dichromate

The reaction can be given as:

4FeCr2O4 + 8Na2CO3 + 7O2 → 8Na2CrO4 + 2Fe2O3 + 8CO2

Preparation of Potassium Permanganate – KMnO4

We can get this (KMnO4) by reacting MnO2 with an alkali metal hydroxide and KNO3 (oxidizing agent).

Therefore, preparation of potassium permanganate involves a reaction of MnO2 with KOH to give MnO42- followed by electrolytic oxidation of manganate to give permanganate ion, MnO4–.

After this manganese ion salt gets oxidized by peroxodisulphate to permanganate ion as per the reaction given below.

2Mn2+ + 5S2O82- + 8H2O → 2MnO4– +10SO42- + 16H+

Thus the dark purple coloured crystals of potassium permanganate are obtained.

2KMnO4 → K2MnO4 + MnO2 + O2

Properties:

Potassium Dichromate, K2Cr2O7

On heating potassium dichromate decomposes to form potassium chromate, chromic oxide and oxygen.

4K2Cr2O7 → 4K2CrO4 + 2CrO3 + 3O2

It is a powerful oxidizing agent. It oxidizes iodide to iodine.

Cr2O72- + 14H+ + 6I– → 2Cr3+ + 7H2O + 3I2

The compound has bright red crystals and is used for dyeing, staining, and tanning etc.

For a medical purpose, it can be an astringent, antiseptic and caustic. It emits toxic chromium fumes when heated

It is highly corrosive and is a strong oxidizing agent for which, it is used in wood preservatives, pigments manufacture and photochemical processes.

Potassium permanganate, KMnO4

When potassium permanganate is heated it gives potassium manganate, manganese dioxide and oxygen.

2KMnO4 → K2MnO4 + MnO2 + O2

It is a powerful oxidizing agent in acidic or alkaline solution.

It is in the form of purple crystals and gets soluble in hot water




Avni2007: can you mark brainiest
Answered by Sanskarjaggi
2

Preparation of Potassium Dichromate – K2Cr2O7

Potassium dichromate is an important chemical used in industries as an oxidizing agent and for the preparation of many other compounds.

Dichromates are usually prepared from chromates and this is obtained by the combination of chromite ore with sodium/potassium carbonate in the presence of air.

Potassium Dichromate

Potassium Dichromate

The reaction can be given as:

4FeCr2O4 + 8Na2CO3 + 7O2 → 8Na2CrO4 + 2Fe2O3 + 8CO2

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