9 Ionic Bond Examples in Daily Life

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All the matter present in the universe is made up of some combination of 118 elements we see on the periodic table. Chemical bonding is a key concept in chemistry to understand how these elements join up to form compounds. For atoms to form compounds large enough to be observed, they must combine with other atoms. It is a well-established fact that opposite charges attract each other via a simple electromagnetic force. Hence, the negatively charged electrons that are orbiting the nucleus and the positively charged protons in the nucleus attract each other. An electron positioned between two nuclei will be attracted to both of them, and the nuclei will be attracted toward electrons in this position. Therefore, in simple terms, a chemical bond is known as a mutual attraction between two or more atoms that results in the redistribution of their outermost valance electrons. The type of chemical bond formed depends upon the elements involved and their corresponding properties. One of such properties is electronegativity. It is the measure of the tendency of an atom to attract the shared pair of electrons. The bond formed between oppositely charged ions, or two atoms due to a significant difference between their electronegativities, is known as an ionic bond. It is one of the main types of bonding along with covalent bonding and metallic bonding.

Ionic bonding tends to occur between electropositive metals and electronegative non-metals. When ionic bonds form, a metal donates one or more electrons, due to having a low electronegativity, to form a positive ion or cation. The non-metal atom has a high electronegativity, and therefore readily gains electrons to form a negative ion or anion. The two ions are then attracted to each other by electrostatic forces. The interspersing of positive and negative ions allows the ions to come close together until the repulsions balance the attractions. However, it is important to understand that electrons do not make a complete transfer from one atom or molecule to the other. In fact, all ionic compounds have some degree of electron sharing (covalent nature). Therefore, the term “ionic bond”  is given when the ionic character is large enough to dominate over the polar covalent character. Moreover, the ionic compounds tend to form a crystal structure rather than being a molecule. Let’s discuss a few examples of ionic bonding in daily life.

1. Table Salt

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(Left) NaCl, a typical ionic compound. (Right) In the crystal structure of sodium chloride, the purple spheres represent sodium cations, and the green spheres represent chloride anions

Perhaps the most common ionic compound people come across every day is table salt. The chemical name of table salt is sodium chloride, NaCl. It has a cubic unit cell. NaCl is best thought of as a face-centered cubic array of anions with an interpenetrating fcc cation lattice (or vice-versa). The cell looks the same whether you start with anions or cations on the corners. Each ion is 6-coordinate and has a local octahedral geometry. NaCl forms easily through the combination of its component elements sodium and chlorine.

{2Na} (s) + {Cl}_{2} (g)  →  2 NaCl

The reaction is extremely exothermic, producing a bright yellow light and a great amount of heat energy. The attractions between the {Na}^{+} and {Cl}^{-} ions in the solid are so strong that only highly polar solvents like water dissolve NaCl well. Salt plays a crucial role in maintaining human health. It is the main source of sodium and chloride ions in the human diet. Sodium is essential for nerve and muscle function and is involved in the regulation of fluids in the body. Whereas, chloride ions serve as important electrolytes by regulating blood pH and pressure.

2. Iodized Salt

iodized salt

Iodine is one of the essential dietary minerals that is required in the human body for normal thyroid function, growth, and cognitive development. Worldwide, around 1.9 billion people suffer from iodine deficiency and almost a quarter of which are school-aged children. To overcome these challenges, governments around the globe launch several awareness campaigns promoting the use of iodized salt over plain salt. Iodized salts are a mixture of table salt with some salt of iodine, most commonly potassium iodide KI. Since it can be added to a common food item without altering the taste, it is an easy way to get iodine in the diet. Potassium Iodide KI is produced using elemental iodine and potassium hydroxide, or in more scientific terms:

4. Baking Soda

baking soda

Baking soda is another most commonly found chemical in a household, specifically in the kitchen. It is one of the most vividly used leavening agent used in baking goods to improve their texture and appearance. In chemistry, it is known by the name sodium bicarbonate (IUPAC name: sodium hydrogen carbonate) and exists in nature as a crystalline structure, nahcolite, which is later ground to form a fine- powdered baking soda. It is an alkaline chemical compound with the formula {NaHCO}_{3}. Sodium cation {Na}^{+} and a bicarbonate anion {HCO}_{3}^{-} are held together via ionic bonding to form this salt. Sodium bicarbonate is generally amphoteric in nature; however, the aqueous solutions are mildly alkaline due to the formation of carbonic acid and hydroxide ion:

{HCO}_{3}^{-} + {H}_{2}{O} {H}_{2}{CO}_{3} + {OH}^{-}

The amphoteric nature of sodium bicarbonate allows it to react with both acids and bases. For instance, you might have witnessed the volcano model somewhere during your schooling. The common ingredients for that model are sodium bicarbonate (baking soda) and vinegar (acetic acid). When they react in a closed environment inside that model, the canon dioxide released in the reaction becomes trapped and erupts from the mouth of the volcano, demonstrating a volcanic eruption. The compounds inside the bottle react as follow:

{NaHCO}_{3}^{-} + {CH}_{3}{COOH} {CH}_{3}{COONa} + {H}_{2}{O} + {CO}_{2}

Moreover, one must not confuse baking soda with baking powder. While both the compounds may look similar, baking powder is a mixture of baking soda, cream of tartar (a dry acid), and sometimes cornstarch.

5. Washing Soda

washing soda

Washing soda is an essential chemical compound found in laundry detergent powders and liquids. It is used to remove stubborn stains from laundry. The chemical name for washing soda is sodium carbonate decahydrate, {Na}_{2}{CO}_{3}{.10}{H}_{2}{O}. It is the most common hydrate of sodium carbonate containing 10 molecules of water of crystallization. Sodium carbonate ( {Na}_{2}{CO}_{3} ) is a salt composed of two sodium ions ({2Na}^{+}) and one carbonate ion ({CO}_{3}^{2-}). When dissolved in water, carbonate ions successfully removes the protons from the water and form hydroxide ions and bicarbonate ions. This increases the overall ({OH}^{-}) ions, which in turn increases the pH and makes it more alkaline.

{CO}_{3}^{2-} + {H}_{2}{O} {HCO}_{3}^{-} + {OH}^{-}

sodium carbonate

On a commercial scale, sodium carbonate is produced mainly by three processes: Leblanc Process, Solvay’s Process, and Hou’s Process. However, it can also be prepared in the laboratory from a similar salt, sodium bicarbonate.

{NaHCO}_{3}^{-} + {NaOH} {Na}_{2}{CO}_{3} + {H}_{2}{O}

Apart from acting as a detergent, washing soda helps in cleaning cloths by softening the hard water. Hard water contains dissolved compounds, usually calcium or magnesium compounds. Sodium carbonate is used for removing the temporary and permanent hardness of the water. Since sodium carbonate is water-soluble and magnesium carbonate and calcium carbonate are insoluble, the removal of Mg2+ and Ca2+ is done by treating them with carbonate ions, to form insoluble solid precipitates:

{Ca}^{2+}(aq) + {Na}_{2}{CO}_{3}(aq) → {CaCO}_{3} + 2{Na}^{+}

{Mg}^{2+}(aq) + {Na}_{2}{CO}_{3}(aq) → {MgCO}_{3}(aq) + 2{Na}^{+}

6. Household Bleach

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Bleach is a name given to all the compounds that are used for cleaning stains and/or removing color from fabric. It often refers, specifically, to a dilute solution of sodium hypochlorite, also called “liquid bleach”. Sodium hypochlorite (NaOCl), also known as hypochlorous acid, is a salt comprising a sodium cation ({Na}^{+}) and a hypochlorite anion ({OCl}^{-}). Anhydrous sodium hypochlorite is unstable and decomposes explosively. Therefore, it is hydrated with 5 molecules of water of crystallization to form {NaOCl}{.5H}_{2}{O}, which is a non-explosive pale greenish-yellow solid. At room temperature, sodium hypochlorite is more stable in dilute solutions that contain solvated {Na}^{+} and {OCl}^{-} ions. If sodium hypochlorite is not properly stored in airtight containers, it may react with carbon dioxide to form sodium carbonate.

bleach

2{NaOCl} + {CO}_{2} + {H}_{2}{O} {Na}_{2}{CO}_{3} + 2{HOCl}

However, household bleach contains only 3–8% of sodium hypochlorite, by weight, along with 0.01–0.05% sodium hydroxide. The purpose of adding sodium hydroxide is to slow the decomposition of sodium hypochlorite into sodium chloride and sodium chlorate.

7. Preservative 

sodium benzoate

To keep up with the pace of the ever-developing world, people rely more and more on packaged foods and drinks. Nevertheless, there is always some concern about the contamination of packed food due to the growth of microorganisms such as yeast and bacteria. Thankfully, preservation techniques have come a long way in the past few years, allowing manufacturers and companies to increase the shelf life of their products and significantly lower the risk of food-borne illness. Sodium benzoate ({C}_{6}{H}_{5}{COONa}) is one such preservative that prevents the growth of microorganisms such as bacteria and fungi, and slow the oxidation of fats that cause rancidity. It is denoted by the E number E211 on the food products.

sodium benzoate (2)

Whenever sodium benzoate dissolves in water, it dissociates into sodium cation {Na}^{+} and benzoate anion {C}_{6}{H}_{5}{COO}^{-}. Another example of a preservative is sodium sulfite {Na}_{2}{SO}_{3}. This is an inorganic compound that comprises of two sodium ions ({2Na}^{+}) and one sulphite ion ({SO}_{3}^{2-}). It is denoted by the E number E221 on the food products. As a reducing agent, it is used as a preservative to prevent dried fruit from discoloring.

8. Anti-caking Agent

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When we talk about powdered food materials, such as flour, sugar, dried milk, dried vegetables, dried fruits, bakery mixes, soup powders, spice mixes, juice powders, etc, the common challenge encountered with them during the rainy or humid weather conditions is the formation of lumps. This process in technical terms is known as caking. It is a consequence of the chemical reactions of grain surfaces. Often these reactions involve adsorption of water vapor or other gases. This issue is addressed by placing anticaking additives in the food products. The mechanism involves absorbing excess moisture or coating particles and making them water-repellent. One such anti-caking agent that can be found in table salt is magnesium carbonate, {MgCO}_{3}. It is an inorganic salt that is a white solid that comprises of two magnesium ions ({2Na}^{+}) and one carbonate ion ({CO}_{3}^{2-}). Because of its low solubility in water and hygroscopic properties, {MgCO}_{3} was first added to salt in 1911 to make it flow more freely by Morton Salt company.

9. Ingredients in Antacids

antacids

Most of us enjoy spicy food, every now and then. In order to digest that food, sometimes our gastric glands secrete excess acid and we experience acidity. Antacids are the most commonly used product for treating heartburn discomfort caused by that extra acid. They are the fastest chemical compounds available in the market to neutralize the acid in your stomach. Most of the antacids that are available over the counter consist of several ionic compounds, such as magnesium carbonate, magnesium trisilicate, calcium carbonate, and sodium bicarbonate.

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