Some Important Compounds of Sodium: Sodium Carbonate, Sodium Bicarbonate, Sodium Chloride, Sodium Hydroxide

Some Important Compounds of Sodium: The better forms of ‘common salt’ are sodium salts. Even though it is difficult to imagine food without salts, this element is used in a variety of industries. As a result, it is one of the most desired and useful elements on the planet earth. To read the important compounds of Sodium, read the below article.

Study Sodium Acetate Formula Here

Sodium Carbonate (Washing soda), \({\rm{N}}{{\rm{a}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}\)

Anhydrous sodium carbonate is also called soda ash as it is present in the ashes of certain marine plants. Until \(1790,\) this was the only natural source. Washing soda, \({\rm{N}}{{\rm{a}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}{\rm{,}}\) is widely used in laundry to clean clothes. Though there are several methods available, the Solvay Ammonia Process is the most commonly used to produce anhydrous sodium carbonate.

Sodium Carbonate Theory

Carbon dioxide is passed through a concentrated solution of sodium chloride or brine (about \(30\% \)) that is saturated with ammonia to produce sodium hydrogen carbonate as follows:

Sodium hydrogen carbonate precipitates to form in the presence of \({\rm{N}}{{\rm{a}}^{\rm{ + }}}\) ions in the solution. Filtration is used to remove the precipitate, which is then heated to produce sodium carbonate.

Sodium Carbonate Manufacture Process

The plant used for the manufacturing process is shown below:

Solvay Ammonia Process for the Manufacture of \({\rm{N}}{{\rm{a}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}\)

a. Ammoniation Tower: A saturated brine solution \(\left( {{\rm{30\% }}} \right)\) is introduced into the top of the iron tower, while gaseous ammonia from the ammonia recovery tower is introduced below. As a result of this countercurrent process, the brine becomes saturated with ammonia, while calcium and magnesium impurities in commercial sodium chloride precipitate as insoluble carbonates.

The resulting ammoniated brine is filtered to remove precipitated calcium and magnesium carbonates before being routed through the carbonation tower.

b. Carbonation tower: It is made of iron and has a number of perforated horizontal partitions. The clear ammoniated brine solution is trickled down from the tower’s top, while carbon dioxide from the lime kiln is introduced from the bottom at a pressure of \(1-2\) atmospheres. Carbon dioxide rises through the small holes, combining with ammoniated brine to form sodium bicarbonate. Throughout the process, a temperature of \({\rm{300 – 310K}}\) is maintained.

\({\rm{NaCl + N}}{{\rm{H}}_{\rm{3}}}{\rm{ + C}}{{\rm{O}}_{\rm{2}}}{\rm{ + }}{{\rm{H}}_{\rm{2}}}{\rm{O}}\, \to \,{\rm{NaHC}}{{\rm{O}}_3}\left( {\rm{s}} \right) + {\rm{N}}{{\rm{H}}_{\rm{4}}}{\rm{Cl}}\left( {{\rm{aq}}} \right)\)

c. Filtration: Tiny crystals of sodium bicarbonate can be found in the solution flowing out of the carbonation tower. These are filtered by running them through vacuum filters.

d. Calcination of sodium bicarbonate: Sodium carbonate is formed when the sodium bicarbonate obtained above is strongly heated or calcined in a kiln.

\({\rm{2NaHC}}{{\rm{O}}_{\rm{3}}}\, \to \,{\rm{N}}{{\rm{a}}_2}{\rm{C}}{{\rm{O}}_3} + {\rm{C}}{{\rm{O}}_2}{\rm{ + }}{{\rm{H}}_2}{\rm{O}}\)

e. Ammonia recovery tower: In this tower, ammonia is formed by the reaction between \({\rm{N}}{{\rm{H}}_{\rm{4}}}{\rm{Cl}}\) and \({\rm{Ca}}{\left( {{\rm{OH}}} \right)_{\rm{2}}}{\rm{,}}\) and the reaction mixture is heated with the help of a steam coil.

Ammonium hydrogen carbonate present in the tower also decomposes to evolve \({\rm{N}}{{\rm{H}}_{\rm{3}}}\) and \({\rm{C}}{{\rm{O}}_{\rm{2}}}{\rm{.}}\)

Both these gases are pumped into the ammoniation tower, where they take part in the reaction.

Properties of Washing Soda

• 1. Sodium carbonate is a white crystalline solid that exists in the form of a decahydrate, \({\rm{N}}{{\rm{a}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}{\rm{.10}}{{\rm{H}}_{\rm{2}}}{\rm{O,}}\) also known as washing soda.
• 2. It dissolves in the water quite easily, and its aqueous solution is alkaline in nature because of hydrolysis.
• \({\rm{N}}{{\rm{a}}_2}{\rm{C}}{{\rm{O}}_{\rm{3}}}\, + 2{{\rm{H}}_{\rm{2}}}{\rm{O}} \to \,\mathop {2{\rm{NaOH}}}\limits_{\left( {{\rm{Strong}}\,\,{\rm{base}}} \right)} \,{\rm{ + }}\,\mathop {{{\rm{H}}_2}{\rm{C}}{{\rm{O}}_3}}\limits_{\left( {{\rm{Weak}}\,\,{\rm{acid}}} \right)} \)
• 3. The action of heat: Upon heating up to \({\rm{373 \;K,}}\) it slowly loses nine molecules of water of crystallisation and changes into monohydrate.

• 4. The action of acids: Sodium carbonate reacts with both diluted \({\rm{HCl}}\) and diluted \({{\rm{H}}_{\rm{2}}}{\rm{S}}{{\rm{O}}_{\rm{4}}}\) to produce \({\rm{C}}{{\rm{O}}_{\rm{2}}}\) gas, which is accompanied by vigorous effervescence.

Uses of Washing soda

• 1. It is used in the production of soap, glass, paper, caustic soda, borax, and other products.
• 2. When combined with \({{\rm{K}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}{\rm{,}}\) it is used as a fusion mixture.
• 3. It is known as washing soda and is used in the washing of clothes.
• 4. It is used in the textile industry as well as in petroleum refining.
• 5. It is used in laboratories as a reagent.

Sodium Chloride \(\left( {{\rm{NaCl}}} \right)\)

Preparation of Sodium Chloride

Seawater is the most abundant source of sodium chloride, accounting for \(2.7\) to \(2.9\) per cent by mass. In tropical countries such as India, common salt is typically obtained through the evaporation of seawater. Solar evaporation produces approximately 50 lakh tonnes of salt in India each year. Impurities of sodium sulphate \(\left( {{\rm{N}}{{\rm{a}}_{\rm{2}}}{\rm{S}}{{\rm{O}}_{\rm{4}}}} \right){\rm{,}}\) calcium sulphate \(\left( {{\rm{CaS}}{{\rm{O}}_{\rm{4}}}} \right){\rm{,}}\) calcium chloride \(\left( {{\rm{CaC}}{{\rm{l}}_{\rm{2}}}} \right){\rm{,}}\) and magnesium chloride \(\left( {{\rm{MgC}}{{\rm{l}}_{\rm{2}}}} \right)\) are present in crude sodium chloride obtained by the crystallisation of brine solution.

Since \({\rm{MgC}}{{\rm{l}}_{\rm{2}}}\) and \({\rm{CaC}}{{\rm{l}}_{\rm{2}}}\) are deliquescent, impure common salt becomes wet during the rainy season. To produce pure sodium chloride, the crude salt is dissolved in a small amount of water and then filtered to remove insoluble impurities. When crystals of pure sodium chloride separate, the solution is then saturated with hydrogen chloride \(\left( {{\rm{HCl}}} \right)\) gas. Because calcium and magnesium chloride are more soluble, they remain in solution.

Properties of Sodium Shloride

• 1. Pure sodium chloride has no hygroscopic properties.
• 2. It melts at \({\rm{1081 \;K}}{\rm{.}}\)
• 3. At \({\rm{273 \;K,}}\) its solubility is \({\rm{360 \;g}}\) per litre of \({{\rm{H}}_{\rm{2}}}{\rm{O}}{\rm{.}}\) However, as the temperature rises, the solubility does not increase noticeably.

Uses of Sodium Chloride

(i) It is used as a common salt or table salt for domestic purposes.
(ii) It is used in the manufacturing of \({\rm{N}}{{\rm{a}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}{\rm{,}}\) \({\rm{NaOH,}}\) and \({\rm{N}}{{\rm{a}}_{\rm{2}}}{{\rm{O}}_{\rm{2}}}{\rm{.}}\)

Sodium Hydroxide (Caustic soda), \({\rm{NaOH}}\)

Preparation of Sodium Hydroxide

In most cases, sodium hydroxide is produced commercially by electrolysis of sodium chloride in a Castner-Kellner cell. Using a mercury cathode and a carbon anode, a brine solution is electrolysed. Sodium amalgam is formed when sodium metal is discharged at the cathode combines with mercury. At the anode, chlorine gas is produced.

The amalgam is treated with water to give sodium hydroxide and hydrogen gas.

Physical properties of Sodium hydroxide

• 1. Sodium hydroxide is a white crystalline solid with a melting point of \({\rm{591 \;K}}{\rm{.}}\)
• 2. It is highly soluble in water, producing a strong alkaline solution that tastes bitter, is corrosive, and feels soapy to the touch.
• 3. \({\rm{NaOH}}\) crystals are liquescent.
• 4. The surface sodium hydroxide solution reacts with atmospheric \({\rm{C}}{{\rm{O}}_{\rm{2}}}\) to form sodium carbonate crystals.

Uses of Sodium hydroxide

• 1. It is used in the production of soap, paper, artificial silk (rayon), and other products.
• 2. It is used in petroleum refining and bauxite purification.
• 3. In the textile industry, it is used to mercerise cotton fabrics.
• 4. It is used in the manufacture of pure fats and oils.
• 5. It is used in the production of dyes and a variety of other chemicals.
• 6. It is used in laboratories as a reagent.

Sodium Hydrogen Carbonate (Baking soda), \({\rm{NaHC}}{{\rm{O}}_{\rm{3}}}\)

Sodium hydrogen carbonate is commonly called baking soda because on heating it decomposes to release bubbles of \({\rm{C}}{{\rm{O}}_{\rm{2}}}\) (leaving holes in cakes or pastries and making them light and fluffy).

Preparation of Sodium Hydrogen Carbonate

Baking soda can be made in the laboratory by passing an excess of carbon dioxide gas through a saturated solution of sodium carbonate. Sodium hydrogen carbonate is formed as a result. It precipitates because it is only sparingly soluble in water. Without heating, the precipitate is separated, washed, and dried.

\({\rm{N}}{{\rm{a}}_2}{\rm{C}}{{\rm{O}}_{\rm{3}}}\, + {\rm{C}}{{\rm{O}}_2} + {{\rm{H}}_{\rm{2}}}{\rm{O}} \to \,2{\rm{NaHC}}{{\rm{O}}_3}\)

Properties of Baking Soda

\( \to \) Sodium hydrogen carbonate is a white crystalline solid and is stable in the air.
\( \to \) Upon heating at \({\rm{523 \;K,}}\) it decomposes to give sodium carbonate.

\( \to \) When it reacts with dilute mineral acids, it evolves carbon dioxide gas, which is accompanied by quick effervescence.

Uses of Sodium hydrogen Carbonate

1. It is used in fire extinguishers.
2. It is used as a constituent in baking powder (a mixture of sodium hydrogen carbonate and tartaric acid).
3. It is used as a mild antiseptic for skin diseases and also as an antacid to neutralise stomach acidity.
4. It is used in effervescent drinks.
5. It is used as a reagent in the laboratory, particularly in volumetric analysis.

Summary

Sodium carbonate, sodium chloride, sodium hydroxide, and sodium hydrogen carbonate are all industrially important sodium compounds. These compounds have a wide range of uses in industry, agriculture, medicine, as well as at home. Several industries use sodium compounds on a large scale to manufacture products such as soap, petroleum, chemicals, textiles, etc.

FAQs on Some Important Compounds of Sodium

Q.1. What are some Important Compounds of Sodium?
Ans: The most important compounds of Sodium are sodium chloride \(\left( {{\rm{NaCl}}} \right){\rm{,}}\) sodium hydroxide \(\left( {{\rm{NaOH}}} \right){\rm{,}}\) sodium carbonate \(\left( {{\rm{N}}{{\rm{a}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}} \right){\rm{,}}\) and sodium bicarbonate \(\left( {{\rm{NaHC}}{{\rm{O}}_{\rm{3}}}} \right){\rm{.}}\)

Q.2. Which element can form a compound with Sodium?
Ans: The most common element which forms a compound with Sodium is chlorine. It forms a compound called sodium chloride. Sodium chloride is the most common compound of Sodium.

Q.3. What are the properties of Sodium?
Ans: The physical properties of Sodium are as follows:
1. Sodium is a soft metal, reactive and with a low melting point, with a relative density of \(0.97\) at \({\rm{20}}\,^\circ {\rm{C}}.\)
2. Sodium has a strong metallic lustre and a colour that is very similar to silver. When exposed to air, sodium compounds tarnish more quickly than potassium compounds.

Q.4. What are the uses of sodium compounds?
Ans: The uses of compounds of Sodium are as follows:
1. Washing soda is used in the production of soap, glass, paper, caustic soda, borax, and other products.
2. When combined with \({{\rm{K}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}{\rm{,}}\) it is used as a fusion mixture.
3. Sodium chloride is used as a common salt or table salt for domestic purposes.
4. Sodium chloride is used in the manufacturing of \({\rm{N}}{{\rm{a}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}{\rm{,}}\) \({\rm{NaOH,}}\) and \({\rm{N}}{{\rm{a}}_{\rm{2}}}{{\rm{O}}_{\rm{2}}}{\rm{.}}\)
5. Sodium hydroxide is used in the production of soap, paper, artificial silk (rayon), and other products.
6. Sodium hydroxide is used in petroleum refining and bauxite purification.
7. Sodium hydrogen carbonate is used in fire extinguishers.
Sodium hydrogen carbonate is used as a constituent in baking powder (a mixture of sodium hydrogen carbonate and tartaric acid).

Q.5. Is washing soda a compound of Sodium?
Ans: Yes, washing soda is a compound of Sodium with the chemical formula \({\rm{N}}{{\rm{a}}_{\rm{2}}}{\rm{C}}{{\rm{O}}_{\rm{3}}}{\rm{.}}\)

Study Biological Importance of Sodium and Potassium Here

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