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Baking Soda, Washing Soda, Plaster of Paris

VSAT 2023

Washing Soda

Last updated date: 28th Jan 2023
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Sodium Bicarbonate is the common name for Baking Soda. Natron, a natural deposit primarily made up of Na2CO3, was originally mined by Egyptians in the Middle Ages. It's been used as soap in the past. In 1971, a French scientist named Nicolas Leblanc was the first to produce NaHCO3. In 1846, Austin Church and John Dwight developed a baking soda factory that used carbon dioxide and sodium carbonate.

What is Baking Soda?

Sodium bicarbonate is commonly referred to as baking soda. It is a chemical compound and the formula is given as NaHCO3. It is a salt, which is composed of a sodium cation and a bicarbonate anion. Heating baking soda yields sodium carbonate, and recrystallization of sodium carbonate yields washing soda. It is also referred to as basic salt. There are more chemicals like plaster of Paris baking soda and washing soda.

Let us look at more about plaster of Paris baking soda and washing soda in detail. In addition to that, you can also learn the preparation of baking soda.

About Baking Soda

Let us look at baking soda preparation and the properties of baking soda. Baking soda looks like a white crystalline compound having a slightly salty taste. Its chemical formula is given as NaHCO3. It is generally called sodium bicarbonate.

Preparation of Baking Soda

Baking soda is synthesized using the process called Solvay. Solvay’s process involves the reaction of sodium chloride, carbon dioxide and ammonia in water. The carbon dioxide that is involved is produced through calcium carbonate and the calcium oxide left is used in recovering the ammonia from ammonium chloride. Thereby, sodium bicarbonate can be produced as one of the end products.

NaCl + H2O + CO2 + NH3 → NH4Cl + NaHCO3

Uses of Baking Soda

It can be used in making fluffy and soft bread and cakes due to the production of carbon dioxide when it is either heated or mixed in water. The equation is represented as follows:

NaHCO3 + H+ → CO2 + H2O + Sodium Salt of Acid

It is used in making soda-acid fire extinguishers and as an ingredient in antacids manufacturing.

Plaster of Paris

Plaster of Paris is obtained by heating gypsum. Plaster of Paris' chemical formula is given as CaSO4.1/2H2O. Plaster of Paris is defined as a white powder and on mixing with water, it changes to gypsum resulting in the hard solid mass. It is primarily used by Doctors as a plaster for setting the fractured bones in the right position.

Plaster of Paris is said to be a chemical compound having fine white powder that hardens when exposed to moisture and allowed to dry. It is better referred to as calcium sulfate hemihydrate.

About Plaster of Paris

Generally, the plaster of Paris does not crack or shrink when dry, making it an excellent medium for casting molds. Commonly, it can be used to precast and hold the parts of ornamental plasterwork, which is placed on cornices and ceilings. It's also used to produce plaster casts to keep broken bones immobilized while they recover, however many current orthopedic casts are composed of thermoplastics or fiberglass.

A few sculptors work directly in plaster of Paris, as the speed where the plaster sets give the work a sense of immediacy and enable the sculptor to quickly achieve the original idea. In Renaissance and medieval times, gesso (usually made with plaster of Paris, mixed with glue) was applied to plaster, wood panels, canvas or stone to provide the ground for oil painting and tempera.

An image of Teeth modeled in plaster of Paris, which is a type of gypsum plaster, is given below.

Toxicity of Plaster of Paris

If the plaster of Paris is not properly handled, it may become harmful and dangerous. It is a calcium sulfate hemihydrates having asbestos, silica, and impurities. Upon inhalation, it can lead to permanent lung damage, including other ailments.

The mixing of Plaster of Paris with water is an exothermic reaction that may lead to severe consequences if you have not taken care of it. However, it is often used by children in crafts, arts, decoration, and other purposes. If it is used carefully, it can be fun to use. Certain safety precautions should be followed, which are given as follows:

  • Wear gloves while working with it to avoid any skin contact

  • Wear a mask to prevent from inhaling the powder

  • Do not pour it directly into your hands. Keep hands inside the hardening mixture.

  • Do not wash the Plaster of Paris down the drain as it can set up the drain and pipes clog it.

Types of Plaster of Paris

There exist three types of plaster that are prevalent in use which are given as follows:

Gypsum Plaster

This is produced by heating the gypsum at a temperature of 300℉. Also, if heated more than 392℉, it turns into anhydrite. When you mix the water either with the anhydrite or gypsum plaster powder, it turns into gypsum.

Lime Plaster

The mixture of calcium hydroxide, sand and other inert fillers are defined as Lime Plaster. Limestone is heated to form quick lime and then slaked lime is formed by adding water to it. Often, it is known as either wet putty or white powder.

Cement Plaster

The mixture of Portland cement, suitable plaster, sand, and water is known as cement plaster. It is applied to both the interiors and exteriors to obtain a smooth surface. Often, a final layer of the gypsum plaster is added over the cement plaster.

Preparation of Plaster of Paris

Manufacturing of Plaster of Paris occurs by heating gypsum in rotary kilns at a temperature of 300℉. It is partially dehydrated.

The chemical reaction that takes place is given as follows:

2 (CaSO4.2H2O) → 300 °F → 2(CaSO4).H2O + 2H2O

When you heat gypsum at a temperature of 300℉, it loses the water molecules and turns into the calcium sulfate hemihydrates. At this particular point, it is known as Plaster of Paris. When you mix dry Plaster of Paris with water, it turns back into gypsum. The plaster’s hardening process starts around 10 minutes after the blending process and takes up to 45 mins to complete. The mixture is completely set in the range of 70 to 75 hours.

Uses of Plaster of Paris

Plaster of parrots has plenty of applications and uses across many sectors. From buildings, decoration to arts, dentistry and medical, Plaster of Paris is used in various methods.

A few of them are listed below. Let us look at them in detail.

Building Material

Plaster of Paris can be used as a building material by architects and constructors. Often, it is used as a protective coating on the ceiling and walls before the painting process is started. Alongside this, it also offers a smooth surface, as well as aids in fireproofing.

Moulding and Casting Agent

It is given as an excellent moulding and casting agent for multiple purposes. Many statues, showpieces, including other decoration elements, are made by using plaster of Paris.

Medical Purposes and Applications

In medical departments and hospitals, plaster of Paris is often used in fracture cases. Orthopaedics also uses it to put casts around the bone fractures for various body parts. This offers stiffness and support to the bone and aid in the healing process.


It is used in radiotherapy to manufacture individualized immobilization shells for patients. And, the plaster bandages help to develop the head and neck impression of the patients. The paste of the plaster of Paris is then used to fill the impression and make a dummy plaster.

Decoration Element

Plaster of Paris can be used to make decorative materials and pieces. It is used in making showpieces, statutes and more. In addition, it can be creatively used on walls to make new patterns and designs as a decorative element. Also, it can be used for beautifying false ceilings before painting the walls.

Crafts and Arts

For different arts and craft purposes, both children and adults use Plaster of Paris. Also, it can be used by painters and artists to create beautiful designs or patterns. The use of Plaster of Paris in both arts and craft depends on the applicability and need y.

In Dentistry

Dentists or dental clinics use Plaster of Paris to make teeth casts or moulds. Often, they are used for temporary purposes. It is also used to make replicas of both tissues and teeth. And it is used to make false wax teeth.

For Fireproofing

Plaster of Paris is being used as a fire-resistant in fireproofing products, buildings and fire protection systems. It prevents the fire from spreading as the plaster coating discharges water vapour in case of fire.

Alongside this, it protects either by slowing down the heat transfer into concrete or steel elements preventing the breakdown.

3D Printing

Nowadays, gypsum plaster is significantly being used for 3D printing purposes. In this, water is particularly applied by the inkjet head.

Burial Services

Many funeral houses use Plaster of Paris to rejoin the cut-off parts of dead bodies, either remake the damaged tissues or to fill the wounds.

Washing Soda

Washing soda features as an ingredient in a few cleaning products or as a standalone cleaning agent. It is made by putting baking soda in an oven and is often used in homemade detergent recipes and also used as either a water softener or laundry booster sometimes.

It is an alkaline substance, which can be used for general household cleaning, even for laundry purposes. However, it does not clean clothes perfectly, so using laundry detergents is always recommended for the best expected results.

Preparation of Washing Soda

Often, washing soda is made from the ashes of burned plants, which is why sometimes it is referred to as soda ash. The other way it can be made is by just putting baking soda in the oven. Heating the baking soda in the oven causes a chemical reaction, which changes the baking soda compound by transforming it into washing soda. It is to note that making your own chemicals at home may be extremely dangerous, so it is not recommended to try to make your own washing soda.

There are many uses of plaster of Paris and washing soda. Let us look at the use of plaster of Paris and washing soda in detail.

Uses of Washing Soda

Removes Stains

Washing soda is highly alkaline and can act as a solvent to remove stains.

Unclogs Drains

Boiling water and washing soda can be used to unclog drains.

Removes Greasy Buildup in Pots and Pans

It is used either to remove tough stains from kitchenware or to remove the soap scum from kitchen and bathroom surfaces.

Cleans Outdoor Furniture

Whiteflies control aphids and black spots on roses. Mix this material with water in a spray bottle, and spray it on the plants to help control outdoor pests.

Cleans the Washing Machine

If you put the washing soda into the drum and then use the machine on its hottest setting with the most water, it effectively deep-cleans your washing machine.


Sodium bicarbonate (NaHCO3), sometimes known as baking soda, is a crystalline salt found as a natural mineral in nahcolite deposits. Baking soda's science, this seemingly innocuous salt, has a wide range of domestic and industrial uses, including culinary additives, medicine, and cleaning solutions. Pyrotechnics, fire extinguishers, fungicides, and pesticides all include it, and it may have new applications for organizations looking to lessen their environmental effect. Quick-setting gypsum plaster made of a fine white powder (calcium sulfate hemihydrate) that hardens when moistened and allowed to dry. Plaster of Paris gets its name from the abundance of gypsum found in Paris.

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FAQs on Baking Soda, Washing Soda, Plaster of Paris

1. Give the historical relevance of Plaster of Paris.

It has been known and used since ancient times. First, it was made nearly 9000 years ago and was used by ancient Egyptian, Greek and Roman civilizations. However, a large-scale use was observed when it was needed to be used in all constructions that occurred in Paris.

Following a fire in London in 1666, the King of France ordered that all timber walls be plastered quickly to avoid future fires. Resultantly, large-scale gypsum mining was carried around Paris and gypsum was available in massive quantities.

In the 18th century, Paris became the centre of plaster production. Therefore, the name has evolved as Plaster of Paris.

2. Enlist some examples/uses of washing soda?

There are many chemicals used in the real-time requirements like baking soda washing soda plaster of Paris. Similar to that, washing soda is used to remove the greasy buildup from pans and pots, oven racks, and drip pans. It is very good for removing the tea and coffee stains from plastic and ceramics storage containers. Also, it can even be used in bathrooms to remove the soap scum and around the house for general hard surface cleaning. For cleaning, just mix a solution of 1/2 cup of washing soda with 1 gallon of warm water.

Outside the laundry room, sodium carbonate can also be used by a few textile artists to help dyes adhere to fabrics. Particularly, this is useful when creating natural dyes from plants.

3. Give the properties of washing soda.

There exists many properties of washing soda and look at a few of them. It is given as a chemical compound with the chemical formula Na2CO3, which is also called sodium carbonate, and it is a salt of carbonic acid. A few people use washing soda to clean, especially in hard water, make homemade laundry detergent, and even as a laundry additive to soften water.

Water-rich in minerals like calcium and magnesium is called hard water. Hard water can affect the cleaning power of detergent, but washing soda can bind to minerals that are present in the water, allowing the homemade detergents to better absorb into fabric fibers and get on with the cleaning. This soda should not be confused with baking soda, though they are chemically closely related.