What is Potassium Bromate?
Potassium bromate is an ionic compound or salt which is formed of K+ and BrO3-. It is an inorganic compound. It is a strong oxidizing agent and in India widely used in making bread.
According to a report 84% of various types of bread products contain potassium bromate. Using potassium bromate in breads is very harmful for us as potassium bromate is carcinogen. It is banned in japan, china, UK, Canada, Brazil, Australia and New Zealand. India has also limited its use in food products. Its legal limit in India is 50 parts per million.
Thus, potassium bromate is a white crystalline powder which acts as a strong oxidizing agent and is a bromate of potassium. Potassium bromate is also known by other names such as bromic acid or potassium salt.
Formula of Potassium Bromate
Structure of Potassium Bromate
It is an ionic compound which is formed by the ionic bond between potassium ion (cation) and bromate ion (anion). It shows hexagonal crystal structure.
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Properties of Potassium Bromate
Properties of potassium bromate are listed below –
It is found as white crystalline powder.
It is a strong oxidizing agent.
Its molar mass is 167 g.mol-1.
Its density is 3.27 g.cm-3.
Its melting point is 350 ℃.
Its boiling point is 370 ℃.
It decomposes at higher temperatures.
It is soluble in water. As the temperature increases, its solubility in water also increases. For example, at 0 ℃ temperature, 3.1 gram of potassium bromate is soluble in 100 ml of water while at 40 ℃ temperature, 13.3 grams of potassium bromate soluble in 100 ml of water. It reacts violently with water.
It is insoluble in acetone.
Its crystal structure is hexagonal.
Its non – flammable substance.
Its 157 mg/kg oral dose can be lethal.
It is a carcinogenic substance.
Its pH is in the range of 5 – 9 at 25 ℃ temperature.
Preparation of Potassium Bromate
It is produced by using bromine gas and potassium hydroxide. When bromine gas is passed over the hot potassium hydroxide, it produces potassium hypobromite. Potassium hypobromite on disproportionation gives potassium bromate. Potassium bromide and water are produced as byproducts. Reaction is given below –
3Br2 + 6KOH 🡪 KBrO3 + 5KBr + 3H2O
Another method of preparation of potassium bromate includes electrolysis of potassium bromide solution. On electrolysis of aqueous solution of KBr, potassium bromate is obtained. As at 0 ℃ temperature, potassium bromide shows very much higher solubility than potassium bromate so, after the formation of potassium bromate, solution is cooled to 0 ℃ and all potassium bromate gets precipitated while all potassium bromide remains in the solution.
These both the methods of production of potassium bromate are very much similar to the production of chlorates.
Uses of Potassium Bromate
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Potassium bromate is used in baking as an additive. It has been used as an oxidizing agent and dough conditioner commercially for making breads since 1923. It improves baking properties of flours/ doughs by strengthening the wheat gluten network. Thus, it improves gas retention in baked foods and increases their volume. Till 1980s and 1990s, it was used at large scale by most of the countries but recently its usage has dropped due to its carcinogenic properties.
Its oxidizing nature is the reason of its use as an additive in baking products. It oxidizes sulfhydryl groups of proteins and forms disulfide bridges by joining two molecules of protein. Thus, it helps in cross linking pf protein molecules. This cross linking of protein molecules helps in trapping the gas evolved during baking process more effectively. Action of potassium bromate in protein cross linking is shown below by a diagram –
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Protein chain 1 and 2 become a larger protein molecule by cross linking.
If the baking of dough is not done completely at high enough temperature then a residual amount of potassium bromate will be left in the baked product and if it is consumed raw then being a carcinogen, it is very harmful for health.
It can also be used in the production of malt barley but during its usage in malt production as well guidelines by food and drug administration must be followed.
It has been banned by many countries to use it as a food additive after the report of its carcinogenic properties. According to a study in Japan, potassium bromate causes cancer in rats and mice so it can cause cancer in humans as well. Further studies are still going on.
India has also given the guidelines for its limited use. According to FSSAI, the legal limit of potassium bromate as a food additive is 50 parts per million. Potassium bromate has been removed from the list of permissible additives by FSSAI.
Potassium Bromate: Summary in Tabular Form
This ends our coverage on the topic “Potassium bromate”. We hope you enjoyed learning and were able to grasp the concepts. We hope after reading this article you will be able to solve problems based on the topic. If you are looking for solutions of NCERT Textbook problems based on this topic, then log on to Vedantu website or download Vedantu Learning App. By doing so, you will be able to access free PDFs of NCERT Solutions as well as Revision notes, Mock Tests and much more.
FAQs on Potassium Bromate
1. What is Potassium Bromate?
In the form of white crystals or powder, bromate of potassium (KBrO3) is a potassium bromate. It is an oxidizer used to make the dough more elastic and stronger. Potassium bromate is also prohibited in the European Union, Canada, Brazil, and other areas because it causes cancer in rats and mice. Furthermore, CSE has petitioned the FSSAI to forbid the use of potassium bromate.
For more information, refer to https://www.vedantu.com/chemistry/potassium-bromate
2. Why is potassium bromate bad for human health?
Given that it has been demonstrated to induce gastrointestinal, thyroid, and kidney cancer in animals, potassium bromate may be a CARCINOGEN in people. Numerous bakeries and bread producers in the US have voluntarily stopped using it. Bromated flour can potentially be discovered in significantly higher concentrations in the final product when baking is not done long enough or at a high enough temperature, or when potassium bromate is added in excess.
3. What are the uses of potassium bromate?
In the US, potassium bromate is frequently employed as a flour enhancer. The oxidant potassium bromate also referred to as bromate, is used to strengthen and make the dough more elastic. This helps to bake bread that is consistently whiter. KBrO3 works by stimulating the formation of disulfide bridges from thiol or sulfhydryl groups (S-H) in proteins (S-S). As a result, different protein molecules are cross-linked, resulting in stronger, more continuous gluten aggregates that better trap gases.
For more information, refer to https://www.vedantu.com/chemistry/potassium-bromate
4. Is potassium bromate exam relevant?
The chapter on Acids, Bases, and Salts includes a section on Potassium bromate. It is covered in the CBSE curriculum. By practicing the chapter-by-chapter Important Questions for Class 10 Chemistry, students can improve their test preparation. They can strengthen their conceptual knowledge with the help of these Important Questions with Answers for CBSE Class 10 Chemistry. Therefore, they will benefit from studying the questions and answers while they get ready for exams.
For more information, refer to https://www.vedantu.com/question-answer/represent-potassium-and-bromine-using-class-11-chemistry-cbse-5fd79b95aef1aa270c092593
5. How to prepare potassium bromate?
In 100 ml of water, 28 g of potassium hydroxide that is free of potassium carbonate if possible is dissolved. Potassium hydroxide solution is added 40 g (or 12.5 ml) of bromine, roughly 1 ml at a time, once the mixture has cooled to room temperature. As a result, unstable potassium hypobromite is first produced, which swiftly degenerates into bromide and bromate.
For more information, refer to https://www.vedantu.com/chemistry/potassium-bromate