Preparation of Potash Alum

Introduction

Potash Alum is identified by its octahedral shape, colourless, crystalline solid, and sour taste. The crystal of Potash Alum is widely used in several medical sectors to prepare antiseptics that can heal wounds and to stop bleeding quickly. The addition of diluted Sulfuric acid prevents hydrolysis of Potash Alum.

What is Potash Alum?

Potash Alum is determined as Potassium Aluminium Sulphate, which is a chemical substance encountered as dodecahydrate. The compound is referred to as double salt, can be utilized in medical and pharmaceutical industries across the world. The chemical formula of Potash Alum is written as $\mathrm{KAI(SO_{4})_{2}.12H_{2}O}$. The IUPAC name of the compounds is Aluminium Potassium Sulphate Dodecahydrate, with molecular mass of 258.192 g/mol (anhydrous) and 474.37 g/mol (dodecahydrate).

Figure 1 − Structure of Potash Alum

The density of Potash Alum is 1.725 g/cm3. The polymers of Aluminium are usually found to affect the product composition depends on several conditions including dosage, pH, Hydroxide supplement rate, and mixing.

Aim of the experiment

The main aim of the experiment is to formation of Potash Alum through the crystallization process that involves two major components including Potassium Sulphate and Aluminium Sulphate.

Theory

Potash Alum crystals are formed through a specialized crystallization process. Alum is passed through the crystallization process where the concentrated mixture consists of an equimolar quantity of Potassium and aAuminium Sulphate. The crystals are derived as the products in colourless crystalappearance with sour taste. Potash Alum crystal gives an octahedral shape is usually referred to as fitkari. The chemical reaction for the preparation of Potassium Sulphate or Potash Alum is stated below −

$$\mathrm{K_{2}SO_{4}(aq)\:+\:Al_{2}(SO_{4})_{3}(aq)\:\rightarrow\:K_{2}SO_{4}.Al_{2}(SO_{4})_{3}.24H_{2}O(S)(Potash\:Alum)}$$

Materials required

Some essential equipment and compounds that are required for the completion of the experiment successfully are listed below −

• Aluminium Sulphate

• Dilute Sulphuric acid

• Beakers

• Potassium Sulphate

• Wire gauzes

• Filter paper

• Tripod Stand

• Funnel

• Burner

• Distilled water

• Conical flask

• China dish

Procedure

The procedures is followed to prepare Potash Alum are mentioned below −

• The amount of about 12.5g of Potassium Sulphate is weighted and dissolved in a lower quantity of distilled water in a medium size beaker.

• The compound is then stirred well so that the crystals get properly dissolved in water.

• A conical flask is then taken that is filled with warm water in which 50 g of Aluminium Sulphate and 3ml of dilute Sulphuric acid is mixed well to prepare a clear solution.

• The solution can be filtered with the help of a filter paper is the solution is not mixed well or gives a clear appearance.

• A china dish is then taken to mix two clear solutions properly. The china dish is placed on the burner with the help of wire gauze.

• The mixture is stirred and concentrated well until it reaches its crystalline phase.

• The beaker with cold water is taken and heated for at least 2 hours.

• The Potash crystals are separated gradually and filtered with the help of filter paper from the solution.

• Potash crystals are dried after being washed with cold water by keeping them in between a filter paper or a clean cloth.

• Finally, the crystals are weighed to determine their yield on a chemical balance.

Observation

At the end of the experiment, it is observed that the colourless and octahedral shaped crystals of Potassium Sulphate or Potash Alum are formed ppearance,.

Figure 2 − Uses of Potash alum crystals

The taste of the compounds is sour, highly soluble in water, and can turn blue litmus paper into red. The Potash Alum crystals is used in various purposes including, dyeing, blocking chemicals, lake pigmentation, gourmet food, and fire retardant.

Precautions

The major precautions or safety measures are taken during the experiment stated below −

• A certain amount of dilute Sulphuric acid must be added to prevent or control hydrolysis of Aluminium Sulfate during the formation of saturated Potash Alum solution.

• The concentrated solution must be kept for at least half an hour to cool down completely.

• The concentrated solution is needed to be washedd properly to get stable crystals.

• At the time of the experiment safety, gloves and goggles must be used .

• Disposable or waste materials must be thrown in a prepared place to avoid health hazards, after completion of all experiment processes.

Conclusion

Potash Alum can also be denoted as Potassium Alum when it is in pure form. The chemical formula of Potash Alum is written as $\mathrm{KAI(SO_{4})_{2}.12H_{2}O}$. It appears as white colour crystal with a molar mass of 258.192 g/mol. Potash Alum can also be determined as white alum with the smell of metallic water. The compounds are generally formed by crystallization process in presence of Potassium Sulphate and Aluminium Sulphate.

FAQs

1. How hydrolysis of salt can be prevented during the preparation of Potassium Alum?

The mixture of two inorganic salts in definite proportion generally allows crystallization of double salt. The process is carried out by dissolving Aluminium Sulphate in warm water and a little quantity of dilute Sulphuric acid plays an effective role to prevent salt hydrolysis.

2. What safety measures can be taken during potash alum preparation?

The solution of Potassium Sulphate and dilute water must not be disturbed during the process of crystallization. Warm water should be utilised in order to dissolve the salt properly.

3. What are the major uses of potash alum?

Potash alum is widely utilised in several pharmaceutical industries in the preparation of antiseptics. Apart from these the compound is also applied in purification of impure water, stops bleeding, as mordant for dyeing industry, leather tanning, fireproof textiles, and baking powder.