How Is Potassium Chlorate Prepared and Used in Chemistry?
Potassium Chlorate is an inorganic compound which contains one atom of potassium, three atoms of oxygen and one atom of chlorine elements. It appears as white crystalline powder at room temperature in its pure form. It is also called pot crate and also known by its trade names Fegabit or Fekabit. It was discovered by French Chemist Claude Louis Berthollet in the end of the 18th century. At that time, it was mainly used in fireworks but due to safety reasons the role of Potassium Chlorate in fireworks is almost over. Presently, Potassium Chlorate is banned for use in fireworks in most of the countries.
What is the Chemical Formula of Potassium Chlorate?
Molecular formula of Potassium Chlorate is KClO3. It has cation of potassium and anion of chlorate which is shown below in its structural formula as well.
Properties of Potassium Chlorate
Potassium Chlorate has following physical and chemical properties –
In its pure form, it is a white crystalline solid.
Its molar mass is 122.55 g/mol.
Its density is 2.32 g/cm3.
Its melting point is 356℃.
Its boiling point is 400℃.
It is soluble in water. As the temperature increases, solubility of Potassium Chlorate in water also increases.
It is soluble in glycerol as well.
It is slightly soluble in acetone and liquid ammonia as well.
Its oxidizing properties make it suitable for ignition.
It is hygroscopic.
Its crystal structure is monoclinic.
Potassium Chlorate immediately decomposes if heated in the presence of a catalyst such as MnO2. Reaction is given below –
2KClO3(s) 🡪 3O2(g) + 2KCl(s)
If it is heated in the absence of a catalyst, then on decomposition it gives potassium perchlorate and Potassium Chloride. Reaction is given below –
4KClO3 🡪 3KClO4 + KCl
On further heating potassium perchlorate decomposes into oxygen and Potassium Chloride. Reaction is as follows –
KClO4 🡪 KCl + 2O2
Preparation of Potassium Chlorate
It is the most common chlorate used in industries. Due to its various uses, it is produced in the industries at large scale. For its large - scale production Liebig process is used in the industries.
Liebig Process – In this process Potassium Chlorate is produced by passing chlorine into hot calcium hydroxide and then adding Potassium Chloride in it. Reactions involved are given below –
6Ca(OH)2 + 6Cl2 🡪 Ca(ClO3)2 + 5CaCl2 + 6H2O
Ca(ClO3)2 + 2KCl 🡪 2KClO3 + CaCl2
Other methods of preparation of Potassium Chlorate are as follows -
Electrolysis Method – Potassium Chlorate can also be produced by electrolysis of Potassium Chloride. In this method, we take anode of carbon, platinum or mixed metal oxide and cathode of titanium. Both the electrodes are inserted in the aqueous solution of Potassium Chloride and a current is passed through. As the reaction progresses, Potassium Chlorate precipitates out. After the electrolysis, you can easily obtain the crystals or precipitate of Potassium Chlorate by removing the electrodes from the cell and then filter the cell contents.
Disproportionation Method – For production of Potassium Chlorate in small amounts, a disproportionation method is used. In this method, sodium chloride and sodium chlorate are formed by disproportionation of sodium hypochlorite. Then sodium chlorate undergoes metathesis reaction with Potassium Chloride. Reactions involved are given below
3NaOCl(aq) 🡪 2NaCl(s) + NaClO3(aq)
KCl(aq) + NaClO3(aq) 🡪 NaCl(aq) + KClO3(s)
Caustic Potash – Potassium Chlorate can also be produced by passing chlorine gas into a hot solution of potassium hydroxide. Reaction is given below –
3Cl2(g) + 6KOH(aq) 🡪 KClO3(aq) + 5KCl(aq) + 3H2O(l)
Uses of Potassium Chlorate
Initially, Potassium Chlorate was used in the fireworks industry to give beautiful colors to the fireworks. As it is a strong oxidizing agent, it produces oxygen on decomposition. This helps in the combustion of fireworks. This high amount of heat excites the electrons and they produce beautiful colors in the firework mixture. But soon Potassium Chlorate was used in various illegal activities due its explosive properties. So, presently use of Potassium Chlorate in fireworks is banned in many countries. Apart from this application, it has various other uses. Few of them are listed below –
It is used as an oxidizing agent.
It is used in the preparation of oxygen.
It can be used as a disinfectant.
It is used in safety matches in a very small amount.
It is used in explosives.
It helps in early arrival of the blossoming stage of longan trees. Thus, causing it to produce fruit in the warmer climate.
It is used in firearms and percussion caps.
It is used in propellants.
It is used in combination with silver fulminate in trick noise makers such as snappers, pop – its, bang – snaps etc.
It is used in pyrotechnics.
It is used in smoke grenades.
It is used in laboratories as well.
It is used in chlorate candles or oxygen candles.
It is used in oxygen supply systems of aircrafts, space stations and submarines etc.
It is used in limelights (A type of stage lighting which was used in theaters and music halls in old time) as well.
It is also used as a pesticide.
Molten Potassium Chlorate is used in dramatic screaming jelly babies, Gummy bear, Haribo and Trolli candy etc.
Potassium Chlorate has many applications and is a very useful chemical for many industries, but its explosive or oxidizing properties are being used in illegal and inhuman activities. It is used in Afghanistan for production of improvised explosive devices which are used in many inhuman activities. It was the main ingredient in the car bomb used in 2002 Bali (Thailand) bombings that killed 202 people.
This ends our coverage on the topic “Potassium Chlorate”. 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 and will handle Potassium Chlorate carefully in the lab. If you are looking for solutions to NCERT Textbook problems based on this topic, then log on to the Vedantu website or download the 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 Chlorate: Formula, Properties, and Applications
1. What is potassium chlorate, and what is its chemical formula?
Potassium chlorate is an inorganic chemical compound composed of potassium, chlorine, and oxygen atoms. It is a powerful oxidising agent. The chemical formula for potassium chlorate is KClO₃, which indicates that each molecule contains one potassium atom, one chlorine atom, and three oxygen atoms.
2. What are the key physical and chemical properties of potassium chlorate?
Potassium chlorate exhibits several distinct properties:
- Appearance: It is a white crystalline solid in its pure form.
- Molar Mass: The molar mass of KClO₃ is 122.55 g/mol.
- Melting Point: It has a melting point of 356°C and a boiling point of 400°C, at which it decomposes.
- Solubility: It is slightly soluble in cold water but its solubility increases significantly in hot water.
- Oxidising Nature: It is a strong oxidising agent and can react violently with combustible materials like sugar, sulfur, or red phosphorus upon heating or friction.
3. How is potassium chlorate prepared in a laboratory?
On a small scale, such as in a laboratory, potassium chlorate can be produced through a two-step process. First, a hot, concentrated solution of sodium hypochlorite (NaOCl) undergoes disproportionation to form sodium chlorate (NaClO₃) and sodium chloride (NaCl). Following this, potassium chloride (KCl) is added to the solution. Due to the lower solubility of potassium chlorate compared to sodium chlorate, KClO₃ precipitates out of the solution upon cooling, allowing it to be separated by filtration.
4. What are the major applications and uses of potassium chlorate?
Due to its strong oxidising properties, potassium chlorate has several important applications:
- Pyrotechnics and Fireworks: It serves as an oxygen source to help fuel the combustion, creating bright flashes and colours.
- Safety Matches: It is a key ingredient in the head of a safety match, providing the oxygen needed for ignition when struck.
- Laboratory Use: It is commonly used for the preparation of oxygen gas through thermal decomposition.
- Disinfectants: In some formulations, it is used as a disinfectant and antiseptic agent.
- Agriculture: It is used in some countries to induce flowering in fruit trees like longan.
5. What happens when potassium chlorate is heated? Explain the decomposition reaction.
When potassium chlorate (KClO₃) is heated to its decomposition temperature (around 400°C), it breaks down to form potassium chloride (KCl) and releases oxygen gas (O₂). This is a classic example of a thermal decomposition reaction. The balanced chemical equation for this process is: 2KClO₃(s) + Heat → 2KCl(s) + 3O₂(g). This reaction is fundamental to its use in producing oxygen in labs and as an oxidiser in fireworks.
6. Why is potassium chlorate considered a strong oxidising agent?
Potassium chlorate is a strong oxidising agent because the chlorine atom is in a high oxidation state of +5 and is bonded to three highly electronegative oxygen atoms. Upon heating or in the presence of a reducing agent, it readily releases its oxygen atoms. This release of oxygen facilitates the rapid oxidation of other substances, which is why it reacts explosively with materials like sugar or sulfur. This ability to easily provide oxygen for combustion is the core of its function in applications like fireworks and safety matches.
7. What is the difference between potassium chlorate (KClO₃) and potassium chloride (KCl)?
The primary difference between potassium chlorate and potassium chloride lies in their chemical composition and properties. Potassium chlorate (KClO₃) contains oxygen and is a powerful oxidiser. In contrast, potassium chloride (KCl) contains no oxygen, is chemically stable, and is not an oxidising agent. KCl is an ionic salt commonly used as a fertiliser or salt substitute, while KClO₃ is a reactive compound used in explosives and for oxygen generation. In fact, KCl is one of the stable end products when KClO₃ decomposes.
8. How does a catalyst like manganese dioxide (MnO₂) affect the decomposition of potassium chlorate?
In the thermal decomposition of potassium chlorate, manganese dioxide (MnO₂) acts as a positive catalyst. While KClO₃ decomposes at around 400°C on its own, adding a small amount of MnO₂ significantly lowers the required temperature to about 200°C. The catalyst provides an alternative reaction pathway with a lower activation energy, causing the oxygen to be released much more quickly and at a more controlled rate. The manganese dioxide itself is not consumed in the reaction and can be recovered unchanged at the end.
9. What are the essential safety precautions when handling potassium chlorate?
Handling potassium chlorate requires strict safety measures due to its reactive nature. Key precautions include:
- Avoid Mixing: It must never be mixed or ground with combustible materials like sulfur, carbon, phosphorus, or organic compounds, as this can cause a spontaneous explosion.
- Storage: It should be stored in a cool, dry place away from heat sources and incompatible materials.
- Protective Gear: Always wear safety goggles, gloves, and a lab coat to prevent contact with skin and eyes.
- Avoid Friction and Impact: The solid compound is sensitive to shock and friction, which can trigger decomposition. It should be handled gently.
