Plaster Of Paris, Baking Soda & Washing Soda

Baking Soda, Washing Soda, and Plaster of Paris have widespread applications. Baking soda, chemically known as Sodium Bicarbonate (NaHCO₃), Washing Soda, also known as Sodium Carbonate (Na₂CO₃ )& Plaster of Paris, scientifically known as Calcium Sulfate Hemihydrate (CaSO₄.1/2H₂O), are commonly used compounds and often encountered in different contexts.

Key Terms-: Baking Soda, Bicarbonates, Sodium Carbonate, Caustic Soda, Washing Soda, Cations, Anions, Plaster of Paris 

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Plaster of Paris

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Plaster of Paris is a fast-setting gypsum plaster that consists of a fine white powder called calcium sulfate hemihydrate. When mixed with water and allowed to dry, it hardens into a solid form. 

• Plaster has been known and used since ancient times.
• It gets its name from its origins in the abundant gypsum deposits found in Paris.
• One of the remarkable properties of the Plaster of Paris is that it does not shrink or crack when it dries. 
• It is commonly employed to form and maintain decorative plasterwork on ceilings and cornices. 
• Additionally, in the field of medicine, it is utilised to produce plaster casts that immobilise broken bones during the healing process.

Preparation of Plaster of Paris

Plaster of Paris (POP) is derived from the chemical compound known as calcium sulfate dihydrate, which is commonly referred to as gypsum. 

• The chemical formula for gypsum is CaSO₄.2H₂O. 
• The production of POP involves subjecting gypsum to intense heat, typically at a temperature of around 373 K. 
• At this high temperature, about three-quarters of the water of crystallisation in gypsum is removed.
• This results in the formation of Plaster of Paris.

CaSO₄ · 2H₂O → CaSO₄ · 1/2 H₂O + 3/2 H₂O (Discharged as steam)

Since moisture can cause the plaster to hydrate, this might delay the setting of the plaster. It is therefore kept in moisture-proof containers.

Properties of Plaster of Paris

Plaster of Paris exhibits the following properties,

• Plaster of Paris is a white powder that, when combined with water, forms gypsum crystals.
• Heating it at 473 K results in the formation of anhydrous calcium sulfate.
• It exhibits slow and minimal expansion during the setting process.
• It is known for its ability to prevent cracking on surfaces.
• Plaster of Paris provides a decorative finish for interiors.

Uses of Plaster of Paris

The various uses of POP are mentioned below:

• Creating plaster casts for broken bones to support and protect them during the healing process.
• Making decorative elements such as statues, figurines, and ornaments.
• Repairing cracks or holes in walls and ceilings by filling them with Plaster of Paris and smoothing the surface.
• Crafting handmade moulds for DIY projects, such as candles or soap making.
• Sculpting and modelling for art projects and crafts.
• Creating realistic terrain and landscapes for dioramas or model train layouts.
• Making customised moulds for creating replicas or reproductions of objects.

Toxicity of Plaster Of Paris

(POP) is generally regarded as non-toxic bеcausе it is mostly constituted of calcium sulphate hеmihydratе. Howеvеr, thеrе arе a few things to kееp in mind when it comes to safе handling and potеntial hazards:

1. Inhaling large volumеs of plastеr dust ovеr a lengthy period of time may irritate thе rеspiratory systеm.Whеn working with dry plastеr, it is bеst to usе a dust mask or rеspirator.
2. Dirеct contact with wеt or dry plastеr can causе skin irritation, especially in pеoplе with sensitive skin. It is recommended that protective glovеs bе worn and that prolonged contact with plastеr bе avoidеd.
3. Irritation of thе еyеs: Plaster dust or splashes might irritate thе еyеs. If thе plastеr gеts into your еyеs, rinsе thеm thoroughly with clеan watеr for sеvеral minutes and seek mеdical assistance if thе irritation persists. 

Read More: Amorphous and Crystalline Solids

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Washing Soda

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Washing Soda, also known as sodium carbonate, is a powder that appears whitish and lacks any noticeable odour. Its chemical formula is Na₂CO₃.

• It is hygroscopic, meaning it can absorb moisture from the surrounding air. 
• When dissolved in water, it forms a highly alkaline solution that is soluble.
• The manufacturing of Washing Soda is achieved through the Solvay process.
• It relies on the utilisation of phosphoric acid. 
• In this process, sodium chloride, ammonia, and carbon dioxide act as catalysts.
• The process involves the generation of carbon dioxide from calcium carbonate.

Initially, a solution of sodium bicarbonate is obtained, which is then transformed into sodium carbonate through the application of heat. Finally, Washing Soda is produced by recrystallizing sodium carbonate.

Washing Soda Preparation

The production of Washing Soda involves a series of steps. Initially, sodium bicarbonate is generated, which is subsequently converted into sodium carbonate. Finally, Washing Soda is obtained through the recrystallization of sodium carbonate.

• The Solvay manufacturing process is employed to create washing soda. 
• This process entails a reaction between sodium chloride, ammonia, carbon dioxide, and water.
• As part of this process, carbon dioxide is formed by producing calcium carbonate
• The resulting calcium oxide is utilised to recover ammonia from ammonium chloride.

1. NaCl + NH₃ + CO₂ + H₂O → NaHCO₃ + NH₄Cl
2. 2NaHCO₃ → Na₂CO₃ + H₂O + CO₂
3. Na₂CO₃ + 10H₂O → Na₂CO₃.10H₂O

Uses of Washing Soda

Here are the few uses of Washing Soda:

• Washing soda can be used as a laundry booster to help remove tough stains and odours from clothes.
• It is effective in softening hard water, making it easier for soap to lather and clean effectively.
• Washing soda can be used as a household cleaner for various surfaces, including countertops, sinks,etc.
• It is useful for removing grease and grime from pots, pans, and oven racks.
• Washing soda can be used to unclog drains by dissolving buildup and clearing blockages.

Read More: Carbonates 

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Baking Soda

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Baking soda is a chеmical molеculе with thе formula NaHCO₃ that is also known as sodium bicarbonatе.

• It is a salt consisting of a sodium cation and a bicarbonate anion. 
• When baking soda is heated, it undergoes a chemical reaction and transforms into sodium carbonate.

Preparation of Baking Soda

Baking soda, or sodium bicarbonate, is produced using the Solvay process. This process involves the reaction of sodium chloride, carbon dioxide, and ammonia in water. 

• The carbon dioxide required in the process is generated by reacting calcium carbonate.
• Thе calcium oxidе producеd is utilisеd to еxtract ammonia from ammonium chloridе.
• Through this series of reactions, sodium bicarbonate is formed as one of the final products.

NaCl + H₂O + CO₂ + NH₃ → NH₄Cl + NaHCO₃

Uses of Baking Soda

Few uses of Baking Soda are listed below:

• Baking soda can be used as a natural and gentle cleaner for various surfaces.
• It helps to remove unpleasant odors, such as those in refrigerators or carpets.
• Baking soda is a common ingredient in baking, as it helps the dough to rise and gives a fluffy texture to baked goods.

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Things To Remember

• Plastеr of Paris is a whitе gypsum powdеr that hardеns whеn mixеd with watеr. 
• POP is useful for creating moulds and casts.
• Baking soda can be used for baking, cleaning, deodorising, and relieving heartburn.
• Washing soda can be used for cleaning, removing stains, and balancing pH levels in water.
• Chemical formula of Washing Soda is Na₂CO₃
• Washing Soda is obtained through the recrystallization of sodium carbonate 
• Baking soda, or sodium bicarbonate, is produced using the Solvay process.

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