Category: Chemistry Notes PPT

Lye is an alkaline solution that is produced by the reaction of wood ashes and water. The process is called leaching. Lye is commonly used for making soaps and washing. It can also be considered as a strongly alkaline solution like potassium hydroxide or sodium hydroxide.

Pellets of Caustic Soda Lye

Uses of Lye

The lye chemical has been widely used for several purposes. Many industries consider a separate unit for making lye as they need the chemical as a part of their processing. Let us look at some of the applications of lye in our daily life.

1. Soap Production

Sodium hydroxide lye (or caustic soda lye) and potassium hydroxide lye are widely used in soap production. In general, potassium hydroxide soaps are more readily soluble in water and are softer than the caustic soda lye. These caustic lye soaps are not found to be interchangeable; they have separate sets of properties and are widely used for different purposes. 

Hot process washing is a unique process of washing. It uses a lye soap as the chief ingredient in the process. In this preparation, the lye particles are added to water. Since it is an exothermic reaction (reaction of alkalis with water generates heat), the solution is cooled down before it is added to butter and oils. This mixture is then heated over a period of one to two hours, and the molten solution is then poured into molds. The heating process needed to be slow for gradual and even heating, especially in a slow cooker.  

2. Food Industries

Although lye is mainly used as lye soaps, it has several applications in the food industry as well. It is used in curing several types of food like olives, Nordic lutefisk, lye rolls, bagels, pretzels, century eggs, hominy, mandarin oranges (canned), and Kabak tatlisi (a traditional Turkish dessert using pumpkins). It is also used as an effective tenderizer in different food like Japanese ramen noodles, Chinese noodles, zongzi (dumplings made up of glutinous rice wrapped in bamboo leaves), and Cantonese mooncakes. 

It is called Karwi in Boro and Khar in Assamese and is used in different food preparations, curing, medicines, and even in soaps. In the U.S., different grades of lye chemical are available. The higher grades are used in the food processing industries, while the lower grades are used for cleaning drains, oven cleaners, and de-cloggers.

3. Household Use of Lye

Since lye has several cleaning properties, it has found its application for different household purposes. Lye can react with fats and grease and dissolve them. This chemical reaction is called alkaline ester hydrolysis. These grease-dissolving properties are mainly used for commercial purposes like openers for clogged drains and oven cleaners.

Many households use lye for cleaning purposes. They apply lye solutions to tough grease and stains. After the grease gets dissolved in the lye solution, it is easily removed by rinsing. 

4. Tissue Digestion and Decomposition

The process of alkaline hydrolysis can also be applied to the digestion and decomposition of living tissues and animal carcasses. The carcass is placed in a closed and sealed chamber, and the lye solution in water is added to the chamber. Heat is provided to fasten the process.

 At the end of the reaction, the chamber will have a fluid that looks like coffee. Some remains of the carcass, like bone hulls, might be present. These bones are made up of calcium phosphate, which can be crushed with little force. Since lye is cheap and is readily available, it is commonly used in decomposing carcasses from roadkills. Many bodies can be treated at once in this process.

5. Identification of Fungus

Potassium hydroxide solution (3-10%) can exhibit a change in color in some species of mushrooms like Boletes, Cortinarius, and some species of Agaricus.

Safety Concerns Associated With Lye Solutions

Since Lye solutions are alkaline in nature, they are coarse on human skins. Therefore, proper care must be taken while handling lye solutions. Lye can cause skin blisters when coming in contact. It can also lead to tissue decomposition if a high concentration of lye solution is in contact with the body. 

Therefore, safety precautions are a must for handling lye solutions. Safety gloves, equipment, and covers are necessary. Proper access to washing and medicinal kits must also be kept handy while handling lye solutions.  

Maltase is defined as an enzyme that catalyzes the disaccharide maltose hydrolysis to the simple sugar glucose. This enzyme is present in bacteria, yeast, and plants, and it is thought to be generated by cells of the mucous membrane lining the intestinal wall in humans and other vertebrates. 

Maltase

During the digestion process, starch is partially transformed into maltose by salivary or pancreatic enzymes, called amylases; Maltase is secreted by the intestine and then converts maltose into glucose. The body either uses the glucose or stores it as glycogen, also known as animal starch, in the liver.

Intestinal Enzymes

Six intestinal enzymes are needed for starch digestion, two of which are luminal endo-glucosidases, also known as alpha-amylases. The remaining four enzymes have been identified as various maltases, exo-glucosidases bound to the enterocytes’ luminal surface. The sucrase-isomaltase system was linked to two of these maltase activities (maltase Ib, maltase Ia). The rest of the two maltases with no distinguishing characteristics were named maltase-glucoamylase (also called maltases II and III). Since they all digest linear starch oligosaccharides to glucose, these four maltases are also known as alpha-glucosidase.

It is similar to alpha-glucosidase in several ways, but the term “maltase” emphasizes the disaccharide nature of the substrate, where the glucose is cleaved, whereas “alpha-glucosidase” emphasizes the bond, whether the substrate is polysaccharide or disaccharide.

Vampire bats are said as the only vertebrates, which are known to not exhibit intestinal maltase activity.

 

Structure

Maltase is a member of the GH13 (Glycoside hydrolase family 13) of intestinal enzymes that are responsible for transforming complex carbohydrates’ – glucosidase linkages into simple glucose molecules for usage. Then, these glucose molecules would be used as a sort of “food” for cells to produce the energy (it means, Adenosine triphosphate) during Cellular respiration. The genes that can code for maltase are given below:

• Acid alpha-glucosidase that is coded on the GAA gene is required to break down complex sugars known as Glycogen into glucose.

• Maltase-glucoamylase, coded on the MGAM gene, plays a vital role in the digestion of starches. This is because of this enzyme in humans that starches of plant origin are able to digest.

• Sucrase-isomaltase, coded on the SI gene, is required for the digestion of carbohydrates, including sucrose, isomaltose, and starch.

• Alpha-amylase 1, which is encoded by the AMY1A gene, is responsible for cleaving -glucosidase linkages in polysaccharides and oligosaccharides to generate glycogen and starches, which are then catalyzed by the previous enzymes. This gene’s higher quantities in the brain have been represented to lower the risk of Alzheimer’s disease.

Mechanism

The hydrolysis of alpha-glucosidase linkage is the mechanism of all Family GH13 enzymes. Maltase focuses on dissolving maltose, which is a disaccharide with a -(1->4) bond connecting two units of glucose. The substrate size determines the rate of hydrolysis (or the carbohydrate size).

Maltase Deficiency

Acid Maltase Deficiency (AMD), also called Pompe disease, was first described in 1932 by a Dutch pathologist named JC Pompe. AMD is given as a non-sex-linked autosomal recessive condition, where the excessive accumulation of glycogen builds up within the lysosome vacuoles in nearly all types of cells and all over the body. It is the most serious glycogen storage disease that affects muscle tissue.

AMD is also categorized into three separate types according to the age of onset of the symptoms in affected individuals. Infantile (which is Type a), childhood (which is Type b), and adulthood (which is Type c). The AMD type is defined by the gene mutation type, which was localized in 17q23. At the same time, the mutation type will determine the production level of acid maltase. AMD is fatal, and type-a generally dies of heart failure before age one. Type-b die of respiratory failure between 3-24 ages. And, type-c die of respiratory failure at the age of 10-20 of the onset of symptoms.

 

Production of Maltase Enzyme

Starch is partially transformed into maltose during the digestion process by the salivary or pancreatic enzymes known as amylases (amylase maltase); maltase is secreted by the intestine and then converts maltose into glucose. The so-produced glucose is either utilized by the body or can be stored in the liver as glycogen (or called animal starch).

 

Industrial Applications

Alpha-amylase contains an essential function in the degradation of starches, so it is extremely and commonly used in the baking industry of baking. Also, it is mostly used as a means of flavor, enhancing it to improve bread quality. With no alpha-amylase, the yeast would not be possible to ferment.

Commonly, maltose-glucoamylase can be used as a fermentation source as it is capable of cutting starch into maltose that can then be used for brewing sake and beers.

Maltose glucoamylase has been studied outside of brewing by adding complex inhibitors to avoid the hydrolysis of alpha-glucosidase linkages. By inhibiting the linkage cleave, scientists are hoping to devise a drug that is less toxic and more efficient to treat diabetes.

Amino Acids in Maltase

We have learned already that maltase is a very important part of our body mechanism and plays a vital role in it. We have also seen what deficiency of maltase can cause and how it helps in the process of conversion of maltose into glucose. Now let’s understand which amino acids are present in maltase. Studies have shown that tryptophan, histidine, and cysteine are required for both maltase and glucoamylase activities in the kidney enzyme, whereas tryptophan, histidine, and lysine were required for maltase and glucoamylase activities in the intestine enzyme.

Maltase Use in Yeast and its Mechanism

Maltase is a part of our daily life but also it has many daily life applications one of which is bread.  Interestingly, the enzyme maltase, which converts maltose to glucose, is present in the yeast which is used in bread-making. Now let’s understand the mechanism of how maltase helps yeast in the making of bread. A maltose molecule is first absorbed by the yeast cell and maltase then binds it to maltose, splitting it into two or half. Invertase, like sucrose, is a sucrose-breaking enzyme that is also found in yeast cells. This enzyme works on the flour’s small amount of sucrose. These two enzymes invertase and maltase which are responsible for creating a large portion of the glucose required for yeast to ferment and form the final product which is bread.

 

Effect of pH on Enzymes

In chemistry pH is a key term that is commonly heard either it’s experimenting in labs or going through theories, similarly the pH is also connected to enzymes as enzymes are also affected by the changes in the pH level. Many things can be scaled on the basis of pH in chemistry, similarly determining what will be the right pH helps a lot in the case of enzymes too. In this case, the most favorable pH value helps in determining the point at which the enzyme is most active and this point is also known as the optimum pH.

The extreme level of high or low pH values sometimes results in a complete loss of activity in most of the enzymes. pH is also a key factor in maintaining the stability of enzymes. As with the activity, for each of the enzymes, there is also a region of pH optimal stability.

Enzymes their Substrates and the End-products

There are many other enzymes along with maltase that play a vital role in the digestion process in the human body as well as in other processes but in which they form their substrate and an end product. Let’s have a look at a few enzymes including maltase with their substrate and end products.

1. Maltase– The substrate of maltase is maltose which when carried further in the process gives glucose as the final product or end product.

2. Protease– Protease is an enzyme that is produced in the stomach and pancreas. The substrate of protease is protein and the end product is amino acids.

3. Lipase– Lipase is produced in the pancreas; its substrate is lipids which in simple language can also be said as fats and oils for the main end product which are fatty acids and glycerol.

4. Pancreatic amylase– The substrate of pancreatic amylase is starch which finally forms maltose as its final product and is also produced in the pancreas.

5. Salivary amylase– Salivary amylase is produced in the salivary glands as can be understood by the name itself; its substrate is starch and the end product is maltose.

Mercury is defined as a chemical element having the symbol Hg. It has an atomic number of 80. Quicksilver is the new name for hydrargyrum, which was formerly known as hydrargyrum. Mercury is the only metallic element, which is in the liquid state at standard temperatures and pressures. It is a heavy, silvery d-block element. The only other liquid element at these temperatures and pressures is the halogen bromine, however metals like caesium, gallium, and rubidium dissolve just above room temperature. The density of mercury metal is 13.5 g/mL.

Mercury element is found in cinnabar deposits all over the entire planet (mercuric sulfide). Natural cinnabar or synthetic mercuric sulphide are mixed to make the red pigment vermilion.

Forms of Mercury

Mercury exists in several forms:

• Elemental (metallic) mercury

• Inorganic mercury compounds

• Methyl mercury and other organic compounds

Elemental (Metallic) Mercury

Mercury is a shining silver-white metal that is liquid at room temperature and was originally known as quicksilver. It is also known as elemental or metallic mercury. Older thermometers, fluorescent light bulbs, and some electrical switches include it. When elemental mercury is released, it diffuses into tiny droplets that can flow through small cracks or attach to particular materials. When the elemental mercury is exposed to room temperature, it can evaporate into an odourless, toxic vapour. It turns into a colourless, odourless gas when heated.

Elemental mercury is mercury that hasn’t been reacted with any of the other substances. Mercury produces a compound when it reacts with another substance, such as inorganic mercury salts or methylmercury.

Inorganic Mercury

Mercury is abundant in the environment in its inorganic form, primarily as the minerals cinnabar and metacinnabar, as well as impurities in other minerals. Mercury can instantly combine with chlorine, sulphur, and other elements, forming inorganic salts as a result of weathering. Inorganic mercury salts can travel through water and can be found in soil. Mining deposits of mercury-containing ores can release dust containing these salts into the air.

Coal-fired power plants, the burning of municipal and medical waste, and mercury-using factories can all emit elemental or inorganic mercury. Weathering of rocks containing inorganic mercury salts, as well as factories or water treatment facilities that release mercury-contaminated water, can all contribute to inorganic mercury entering water or soil.

Methyl Mercury

When inorganic mercury salts are able to attach themselves to airborne particles. These particles are deposited on land by rain and snow. Even when mercury is deposited on land, it is frequently released into the atmosphere as a gas or as particles, where it is redeposited.

Emissions of Mercury into the Air

When mercury is released from rock and ends up in the atmosphere and water, it causes a problem for the environment. These discharges might occur in a natural way. Mercury is released into the atmosphere by both volcanoes and forest fires.

Human activities, on the other hand, are responsible for a large portion of the mercury emitted into the environment. Mercury can be released into the air when coal, oil, or wood are burned as fuel, as well as when mercury-containing wastes are burned.

Mercury in the air can fall to the earth in the form of raindrops, dust, or gravity (known as “air deposition”). How much mercury is emitted from local, regional, national, and international sources determines how much mercury is deposited in a given area.

Properties, Uses, and Occurrence

Let us discuss the mercury metal uses, properties and occurrences here.

Properties of Mercury Metal

Mercury was known as early as 1500 BCE in Egypt and most likely in the East. Mercury originally comes from alchemy in the 6th century, when the planet’s symbol was adopted to represent the metal; the chemical symbol Hg comes from the Latin hydrargyrum, which means “liquid silver.” Despite the fact that its toxicity had been known early on, it was mostly used for medical purposes.

Mercury is the only elemental metal that is liquid at room temperature. Cesium melts at around 28.5°C (83°F), gallium melts at about 30°C (86°F), and the rubidium melts at nearly 39°C (102°F). Mercury is silvery white, tarnishes slowly in wet air, and freezes at 38.83°C (37.89°F) into a soft solid similar to tin or lead. At 356.62°C (673.91°F), it boils. 13.5 g/mL is the density of mercury metal. 

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Mercury Metal Uses

It forms amalgams, or liquid alloys, with copper, tin, and zinc. In dentistry, an amalgam with silver is used as a filling. Mercury does not wet or stick to glass, which made it useful in thermometers due to its rapid and consistent volume expansion throughout its liquid range. (In the early 21st century, mercury thermometers were replaced by more accurate electronic digital thermometers.) Its high density and low vapour pressure were also utilised in barometers and manometers.

However, due to mercury’s toxicity, it has been taken out of these instruments. Mercury dissolves gold and silver readily, and this property was once used to extract these metals from their ores.

Mercury’s high electrical conductivity makes it ideal for use in sealed electrical switches and relays. A bluish glow rich in ultraviolet light is produced by an electrical discharge through mercury vapour contained in a fused silica tube or bulb, a phenomenon exploited in UV, fluorescent, and high-pressure mercury-vapour lamps. Pharmaceuticals, as well as agricultural and industrial fungicides, contain some mercury.

The use of mercury in the electrolysis of brine to produce chlorine and sodium hydroxide in the 20th century was based on the fact that mercury used as the negative pole, or cathode, dissolves the sodium released to form a liquid amalgam. Mercury-cell factories for the production of chlorine and sodium hydroxide, on the other hand, were mostly phased out in the early 21st century.

Occurrence

The average amount of mercury found in the Earth’s crust is 0.08 gm (0.003 ounce) per ton of rock. Cinnabar, a red sulphide, is the most important ore. Near volcanoes or hot springs, native mercury is found in isolated drops and occasionally in larger fluid masses, generally with cinnabar. Moschellandsbergite (with silver), potarite (with palladium), and gold amalgam are all extremely rare natural mercury alloys. China produces almost 90% of the world’s mercury, which is often a by-product of gold mining.

Cinnabar is mined in shafts or open pits and refined through flotation. Most mercury extraction methods rely on the metal’s combustibility and the fact that cinnabar is quickly decomposed by air or lime to release the free metal. Cinnabar is used to extract mercury by burning it in the air and then condense the mercury vapour. Because of mercury’s toxicity and the threat of strict environmental controls, researchers have been focusing on better mercury extraction methods.

The fact that cinnabar is very soluble in sodium hypochlorite or sulphide solutions allows the mercury to be recovered via zinc or aluminium precipitation or electrolysis.

Toxicity

Mercury is toxic. Inhalation of the vapour, ingestion of soluble compounds, or skin absorption of mercury can all cause poisoning, so that it is said as mercury metal poisoning. This is the information on mercury metal poisoning.

Mercury in nature is composed of seven stable isotopes:

• 196Hg (0.15 %),

• 198Hg (9.97 %),

• 199Hg (16.87 %),

• 200Hg (23.10 %),

• 201Hg (13.18 %),

• 202Hg (29.86 %), and

• 204Hg (6.87 %).

As a wavelength standard and for other precise work, isotopically pure mercury, composed only of mercury-198 produced by neutron bombardment of natural gold, gold-197, has been used.

Mercury Metal Facts

Mercury in its shining, fast-moving liquid state is beautiful, but don’t touch it! Humans can be extremely poisoned by it. Mercury’s symbol Hg is derived from its Greek name, hydrargyrum, which means “liquid silver” and refers to its shining surface. Because of its mobility, the element is also known as quicksilver.

Methylene blue is a colorful organic chloride salt compound used in medicine and by biologists as a dye to help them see under the microscope. It is also known as Methylthioninium chloride or Swiss blue. It is represented by the formula [C_{16}H_{18}CIN_{3}S]. It was discovered in the year 1876 by German chemist Heinrich Caro.  Historically, it has been widely used in Africa for treating malaria, but now it has been disapproved when chloroquine and other drugs entered the market. Its molecular weight is 319.85 g/mol. It can cause damage to RBCs and also decreases the ability of the blood to carry oxygen which is the primary health concern of humans when exposed to methylene blue via oral or intravenous means. Methylene blue is a thiazine dye that is basic in nature. Methylene blue stains negatively charged cell components like nucleic acids. 

Structure of Methylene Blue

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Structure of Methylene Blue[C_{16}H_{18}CIN_{3}S]

Formula of Methylene Blue

Methylene blue is represented by the formula [C_{16}H_{18}CIN_{3}S]. It has  3,7-bis(dimethylamino) phenothiazine – 5 – ium as the counterion. Its IUPAC name is

7−(dimethylamino)phenothiazin−3−ylidene

7−(dimethylamino)phenothiazin−3−ylidene – methyl azanium; chloride. 

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Preparation of Methylene Blue

1. Methylene blue is prepared by the oxidation of dimethyl-4-phenylenediamine in the presence of sodium thiosulfate. 

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2. By treating the solution of N, N-dimethyl-p-phenylenediamine and N, N, -dimethylaniline hydrochlorides with [H_{2}S] and [FeCl_{3}] or another suitable oxidizing agent.

3. By oxidation of p- amino dimethyl aniline with ferric chloride in the presence of hydrogen sulphide. The dye is zinc chloride double salt of the chloride.

4. N, N-Dimethyl – p – phenylenediamine reacts with sodium thiosulfate to produce thiosulfuric acid which then condenses with N, N-dimethylaniline when it comes in the presence of [Na_{2}Cr_{2}O_{7}] or sodium dichromate to form the indamine, then with copper sulphate and sodium dichromate to the methylene blue.

Related Compounds to Methylene Blue

• Methylene Blue cation

• Azure A

• Azure B

• Methylene green

• 3-(Dimethylamino)-7-(methylamino)phenothiazin-5-ium

• 3,7-Bis(dimethylamino)-4-nitro phenothiazine-5-ium

Properties of Methylene Blue

• Methylene blue is deep blue in colour. 

• Methylene blue exhibits antioxidant properties.

• It also exhibits the property of antidepressants.

• It is highly soluble in water, chloroform, ethanol, and glacial acetic acid.

• It is insoluble in ethyl ether, xylene, and oleic acid.

• It also has the property of being antimalarial.

• It gets decomposed while heating and emits toxic fumes of nitrogen oxides, sulphur oxides, and chlorides. 

• It is non-carcinogenic in nature.

• It is slightly soluble in pyridine. 

• It is basic in nature. It’s a basic thiazine dye. 

• It also exhibits cardioprotective properties. 

• It is non-combustible in nature.

• It acts as the enzyme inhibitor. 

What is the Role of Methylene Blue in the Field of Chemistry?

Methylene blue is widely used in the field of chemistry as a redox indicator in analytical chemistry, that is, to detect the presence or absence of oxygen and other oxidising agents due to the change in colour of the solution to blue when an electron is taken from methylene blue. Also, methylene blue is further used in the analysis of volumetric titrations and in Fehling’s test.

What is the Role of Methylene Blue in the Field of Biology?

Apart from chemistry, methylene blue is also used by biologists in various biological experiments as a stain, for example, for identification and visualisation of bacteria, for identification of nucleic acids, that is, DNA and RNA, or in the techniques of northern blotting or as an alternative to crystal violet chemical and ethidium bromide used in the technique of western blotting. Apart from this, methylene blue is also used to calculate the percentage of viable cells in a yeast sample.

What is the Role of Methylene Blue in the Field of Aquaculture?

The use of methylene blue is not restricted to the only chemical and medicinal field but has also been proved to be very useful in the field of aquaculture for the prevention of bacterial and fungal infections on the eggs of freshwater fish. It also increases the oxygen-carrying capacity of fish’s hemoglobin or for the treatment of fish infected with parasitic protozoan.

Uses of Methylene Blue

• Methylene blue is used in aqua farming for treating fungal infections.

• It is used as an antiseptic in cases of urinary tract infections. 

• It is also used as an indicator during the different chemical reactions.

• It is also used for the treatment of Methemoglobinemia.

• It is also used to dye paper and office supplies, but also to tone up silk colours.

• It is also used in the treatment of septic shock and anaphylaxis.

• It is also used as a dye for a number of staining procedures.

• It is also used as a temporary hair colorant.

• It is used as an oxidation-reduction agent in different chemical reactions.

• It is used in the treatment of pediatric and adult patients with methemoglobinemia.

• It is used as a reagent in oxidation-reduction titrations in volumetric analysis. 

• It is used in the treatment of hypoxia.

• It is used for dyeing cotton and wool. 

• Earlier methylene blue was used to check whether the pasteurized milk is bacteria-free or not. If the colour remains blue, that means milk is pasteurized properly, or else if blue colour disappears that means bacteria is consuming oxygen and the milk is not pasteurized properly.

What are the Warnings Associated with Methylene Blue when it is Used as a Component of a Drug?

Though methylene blue is widely used as a drug, there are certain risk factors associated with its use, due to which there are certain warning labels associated with it. The injections of methylene blue in combination with serotonergic drugs can lead to the serious serotonergic syndrome. Large doses of methylene blue can lead to vomiting, nausea, abdominal pain, dizziness, precordial pain, profuse sweating, headache, hypertension, dyspnea, urinary tract irritation, and mental confusion. It may also lead to the formation of methemoglobin ultimately causing cyanosis. Young infants and patients that have a deficiency of glucose-6-phosphate dehydrogenase can cause hemolytic anemia and hemolysis. Hypersensitivity reactions including generalized urticaria, anaphylaxis, tachycardia, hypotension, and bronchospasm have been reported at the site of injection.

What are the Trade Names of Methylene Blue?

Methylene blue is traded in the market with a variety of names like desmoid Piller, Pantone, desmoid pillen, vitableu, and urolene blue. Methylene blue has many synonym names as well like methylthionine chloride, tetra methylthionine chloride, methylthioninium chloride, Aizen methylene blue, and swiss blue. 

Fun Facts

• It is slightly irritant to the eyes.

• It can cause redness in the eyes tissues if it gets in contact with the eyes.

• If you are having a deficiency of glucose-6-phosphate dehydrogenase, then you should not be treated with methylene blue.

• Symptoms of overdose of Methylene blue are Abdominal or stomach pain, bigger, dilated, or enlarged pupils, dark urine, difficulty breathing, fever, headache, increased sensitivity of the eyes to light, nausea, pale skin, blue staining of the urine, skin, and mucous membranes, rapid heart rate, rapid shallow breathing, etc. 

Most of our routine items are sold in specific numerical quantities along with definite names. For instance, soda cans come in a pack of six, bananas are sold using dozen (12), pens often come in a gross (144 or 12 dozen), papers are packed in reams (500, and not 400 or 600), which seems to be a large number. We know that the magnitude of an atom is very small and it cannot be countable. The uniqueness of each substance is not only defined by the different kinds of ions or atoms present in it, also it depends on the number of ions or atoms present in that substance. For instance, nitrous oxide N₂O, and nitrogen dioxide NO₂, are identical in that their particular molecule consists of oxygen and nitrogen atoms. However, due to their difference in the number of oxygen and nitrogen atoms, those substances exhibit different properties, which require the establishment of a new unit for the measurement of the quantity of substance and any readily quantifiable mass of a compound or an element contains an exceptionally large quantity of atoms, ions, or molecules, which requires an immense numerical unit to count. For this purpose, the mole is used, which seems to be very important for modern chemistry.

What is a Mole?

Mole, also known as mol, is a standard scientific unit in chemistry which is used to measure the large quantities of small things like molecules, atoms, or some other particular particles. Besides, the mole is defined as the number of the International System of Units by the General Conference on Weights and Measures, which was effective from May 20, 2019. Moreover, the number of other particles or atoms is the same for almost all substances in a mole. It is specified as the quantity of any substance constituting the equivalent amount of fundamental units as the identical number of fundamental units in a pure sample of 12C measuring accurately 12 g. Mole in Latin specifies pile, heap, or collection. The number of entities constituting one mole was experimentally found to be 6.022 X 10²³, which is a constant, and it is termed as an Avogadro’s constant (NA) or Avogadro’s number. This constant is always represented in terms of per mole. With Avogadro’s number, researchers can compare and discuss very large numbers, which is useful since substances in our everyday life are composed of a large number of molecules and atoms. Avogadro’s number is essential to understand both the formation of molecules along their combinations and interactions. For instance, since one oxygen atom will merge with two nitrogen atoms to form a nitrous oxide molecule (N₂O), a mole of oxygen (O) (6.022 X 10²³ of O atoms) will incorporate with 2 Moreover, the simplest formula of a compound can be determined by the mole and used to calculate the quantities involved in some chemical reactions. Also, molarity is useful when dealing with reactions of certain solutions. Nevertheless, the number of moles of a solute is defined as molarity in a liter of solution.

What is Molar Mass?

Moles of N atoms (2 × 6.022 × 1023 of N atoms) to form a mole of N₂O.

A mole is an entity that helps us to match the particles of a given substance along with its mass. The molecular weight or molar mass is nothing but the summation of masses of each atom in grams which constitute a mole of a molecule. Molar mass can be determined by dividing the given mass of any substance by the quantity of that substance in g/mol. For instance, the atomic mass of copper is 63.546 amu or 63.546 g/mol. In this 63.546 g of copper, there is a mole or 6.022 X 10²³ copper atoms.

An important feature is that each element’s molar mass is just its atomic mass measured in g/mol. Though, it can also be computed by finding the product of atomic mass given in amu and the constant of molar mass (1 g/mol). For instance, the molar mass of a molecule CaCl₂ can be found out by combining the atomic masses of both calcium (40.078 g/mol) and that of chlorine (2 X 35.45 g/mol), and doing so we will get the molar mass as 110.98 g/mol.

Gram Atomic Mass and Gram Molecular Mass

The gram atomic mass of a substance is defined as the quantity of substance in grams whose numerical va is identical with the atomic mass of that matter. Gram atomic mass seems to be nothing but the mass of a unit mole of an element. It can be measured by using an atomic weight of that element from the periodic table as well as expressing it in grams. So, for example, iron (Fe) has 55.845 u of atomic weight, and so its gram atomic mass is 55.845 g. Therefore, each mole of iron atoms has 55.845 g of mass. 

[ text{Number of gram atoms} =frac{text{mass of the element (g)}}{text{Atomic mass of the element (g)}} ]

Gram molecular mass of any substance is expressed as the quantity of substance in grams whose numerical value is identical with the molecular mass of that substance. Gram molecular mass can be stated as the mass of a unit mole of the molecular substance in grams. It is the same as the molar mass. The only difference is that the gram molecular mass indicates the mass unit has to be utilized. It may be notified in grams per mole or grams (g).

To Find the Gram Molecular Mass

We need to find out the molecular formula to calculate the gram molecular mass. We have to determine the comparable atomic masses of all the constituents in the molecular formula, at first. Then, we have to multiply the subscript after the symbol of every element which represents the number of atoms by their atomic masses. If subscript is not there, then there must be a sole atom of an element present in the molecule. Finally, we need to add all the values to get the required gram molecular mass. For example, the gram molecular mass of nitrogen is 28 g instead of 28 u.

[ {text{Number of gram molecules}} =frac {text{mass of the substance (g)}} {text{molecular mass of the substance (g)}} ]

 

Gram Molecular Volume

It is defined as the volume bound up by a mole of each gas under standard conditions of temperature (273 K) and pressure (1 atm) (at STP). Its value was found to be 22.4 liters for all the gases. It is also called molar volume and it is represented as Vm.

 

1 mole of a gas = 1 Gram Molecular Mass

                            = 22.4 L (STP)

                            = 6.022 X 10²³ molecules.

 

The molar volume of any substance can be expressed using dividing molar mass by its density. 

 

[ {text{Molar Volume}} = frac{text{Molar mass}} {text{density}} ]

The SI unit of molar volume is m3 /mol, practically it is cm3 /mol for solids and liquids and dm3/mol for the gases.

Fun and Interesting Facts about Mole

1. Mole is used in chemistry and other fields like biophysics and biochemistry.

2. The renowned Italian researcher who actually credited the mole is Amedeo Avogadro. However, his full name is Lorenzo Romano Amedeo Carlo Avogadro di Queregna e di Cerreto.

3. If there was a mole of rice grains, the entire terrestrial area in the world would be encased with rice to a certain depth.

4. In 1894, the term mole was coined by Wilhelm Ostwald and was abbreviated from a German word.

5. You know what would be equivalent to the mass of the moon? The mole of hockey pucks.

6. In 2011, the governing bodies consented or gave permission for research options in contrast to the mole.

7. Mole day is celebrated each year on the day of October 23 and is well known among chemistry students, devotees, and chemists in the world.

Naphthalene is a white crystalline volatile solid with a distinct odor that reminds many people of mothballs. At room temperature, the compound sublimes (turns from a solid to a gas) slowly, generating a highly flammable vapor. 

John Kidd (1775–1851), an English chemist and physician, was the first to extract naphthalene from coal tar in 1819. When soft coal is burned in an insufficient quantity of air, coal tar forms, which is a brown to black thick liquid. It is made up of a complex hydrocarbon mixture comparable to that found in petroleum. 

Kidd’s naphthalene extraction was historically significant since it revealed that coal could be used for more than just fuel. It could potentially be used to create chemical compounds with a variety of commercial and industrial applications. 

Richard August Carl Emil Erlenmeyer (1825–1909), a German chemist, discovered the chemical structure of naphthalene. The naphthalene molecule, according to Erlenmeyer, is made up of two benzene molecules linked together. 

Natural sources of naphthalene include petroleum and coal tar. It is extracted by heating the raw material to a temperature of 200°C to 250°C (392°F to 482°F), resulting in middle oil, a mixture of hydrocarbons. After that, the middle oil is distilled to separate its many components, one of which is naphthalene. This naphthalene is cleaned by washing it in strong acid, then in a sodium hydroxide solution, and finally by steam distillation.

 

What is Naphthalene?

Before starting with naphthalene, first, you need to understand what an aromatic compound is. Aromatic compounds are the ring compounds that contain a double and single bond in an alternate manner, and follow the huckel rule. Let’s come to our main question, what is naphthalene? Naphthalene is an aromatic hydrocarbon, consisting of two or more fused aromatic benzene rings. These are polynuclear aromatic hydrocarbons. In short, naphthalene is fused with hydrocarbons. In this article, we have covered the all-important points about naphthalene like the use of naphthalene, structure of naphthalene, and resonance in naphthalene.

 

Structure of Naphthalene

Naphthalene is a member of a polynuclear aromatic hydrocarbon where two aromatic benzene rings are fused together at the ortho position.

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The bond length at the double bond position is around 1.36 Angstrom, and the bond length at the single bond position is around 1.40 angstrom. Naphthalene molecule shows the resonance in its structure. It forms a resonance hybrid. Naphthalene molecules show three resonance structures. These structures are known as canonical structures. Naphthalene forms three resonating structures. These structures are shown below for better understanding.

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In this structure, the pi electrons are delocalised from one position to another. This delocalisation phenomenon leads to the lowering of the electronic energy of the system. In the naphthalene molecule, the carbon 1 – carbon 2 bond length is shorter than the carbon 2 – carbon 3 bond length. All carbons are sp² hybridised and have unused p-orbitals with one electron. In naphthalene, the sigma bond count is eleven.

Properties of Naphthalene:

The physical properties and chemical properties of naphthalene are discussed below:

1. Naphthalene exists in crystalline form.

2. Naphthalene is generally white in color. It is also found in transparent to brownish color.

3. The molecular weight of naphthalene is 128.18 g/mol.

4. Naphthalene is insoluble in water at normal room temperature.

5. Naphthalene has an aromatic odor.

6. The vapor pressure of naphthalene is 0.087 mmHg.

 

Synthesis of Naphthalene

1. From Coal Tar- Naphthalene can be obtained from the coaltar, by making naphthalene crystals. These crystals can be formed by the middle oil fraction. The crystals produced in this process are subjected to sulphuric acid for the purification process. In the end, pure naphthalene crystals are formed.

2. Haworth Synthesis- In this process, benzene to naphthalene is produced. The benzene ring is first subjected to the acylation process. This reaction starts with the Friedel craft Acylation of a benzene ring with the succinic anhydride, then a series of reduction reactions undergo. Finally, a naphthalene molecule is produced by dehydrogenation.

 

Naphthalene in Water

The solubility of naphthalene in water can be determined by its structure. Naphthalene is a polyatomic hydrocarbon. A large number of carbon atoms makes it a hydrophobic molecule. Due to this hydrophobic structure, the naphthalene in water is insoluble. In this article naphthalene, the liquid structure is not discussed in detail.

 

Naphthalene in Other Solvents

Naphthalene is an organic compound with a melting point of 80℃ and a boiling point of 218℃. It sublimes upon heating and is insoluble in water.  In other solvents like ethanol, it is not completely soluble. It is very soluble in benzene, ether and chloroform. 

 

Different Forms of Naphthalene

1. Refined naphthalene

2. Alkyl naphthalene

3. Naphthalene solid

Refined Naphthalene- Refined naphthalene powder is raw material, used for the production of various organic compounds. It is used in agriculture and the fabric industry.

Pyrotechnic special effects such as the formation of black smoke and simulated explosions employ refined naphthalene. It’s highly sublime and won’t dissolve in water. It dissolves in benzene, alcohol, ethers, chloroform, and carbon disulfide. Features of Refined naphthalene include multi-sectoral uses; it has a longer shelf life and is considered effective. 

Alkyl Naphthalene- Alkyl naphthalene generally exists in a form of salt. The most common and widely used alkyl naphthalene is alkyl naphthalene sulfonate sodium salt. It occurs in powder form. The PH of this compound is generally more than 7 (slightly basic in nature). It acts as a surfactant. 

Alkyl Naphthalene is also used to make lubricants. As is expected by customers, lubricants must work even in the most difficult circumstances. Alkyl naphthalene is a choice based on features like stability for long durability and seal compatibility. 

Naphthalene Solid- Naphthalene solid is a very common form of naphthalene. It occurs white in color. It is a crystalline volatile solid. It has an odor like coal tar. 

Naphthalene is obtained from the petroleum distillation of coal tar. It is majorly used in the manufacture of phthalic anhydride. It is also used in repellents for moths. It is an organic compound and the simplest hydrocarbon. 

Use of Naphthalene

The main uses of naphthalene are discussed below:

• Naphthalene is used in making carbaryl drugs. These drugs are used in making insecticides.

• Naphthalene is used in making nadoxolol drug for beta-blocking.

• The Sulphonated form of naphthalene is used as a surfactant.

• Naphthalene is used in making synthetic dyes.

• amino naphthalene sulfonic acid is used in making different types of dyes.

• Molten naphthalene is used for making solvents for an aromatic compound.

 

Did You Know?

• You may be shocked to hear that naphthalene can be present in cigarette smoke, vehicle exhaust, and forest fire smoke.

• In the United States, naphthalene was first licensed as a pesticide in 1948.

• Insecticides include naphthalene.

• Naphthalene is a highly flammable material.

 

Interesting Facts about Naphthalene

• Naphthalene is derived from the Persian word naphtha, which means oil or pitch. 

• Naphthalene is used as a pesticide, for example. The Formosan termite, a species of insect, uses naphthalene to construct its nests. Scientists are still trying to figure out where the termites acquire their naphthalene and why they are immune to its normally lethal qualities. 

• When naphthalene is absorbed into the soil, it becomes a pollutant. Scientists discovered microorganisms capable of digesting naphthalene in the soil in 2003, decreasing the dangers it brings to the environment. 

• Napalm, a mixture of naphthalene and palmitate that ignited and burned at a very high temperature, was one of the most devastating weapons used during the Vietnam War in the 1960s and 1970s, causing widespread damage to plant life, structures, and human life.