Ethene

Ethene

Ethene colorless, flammable gas is the first and typical member of the alkene family. It is produced in large amounts by the cracking and the fractional distillation of petroleum and from natural gas. Ethene is an unsaturated hydrocarbon which is composed of two carbon and four hydrogen atoms. There is a double bond between the two carbons. Each carbon atom of ethene is Sp2 hyberidized which contains three equivalent partially filled Sp2 hybrid orbitals and unhyberidized Pz orbital. The hybrid orbitals are arranged at the three corners of coplaner triangle with an angle of 120º. Two Sp2 hybrid orbitals of carbon atoms overlapp with s atomic orbitals of hydrogen atoms to form a sigma bond between C - H due to the overlapping of Sp2 - S orbitals. The remaining Sp2 hybrid of each carbon atom overlap with the Sp2 hybrid orbital of other carbon atom to form sigma bond between C - C due to the overlapping of Sp2 - Sp2.

The unhyberidized Pz orbital of each carbon atom are situated perpendicular to the Sp2 plane and parallel to the unhyberidized Pz orbitals of two different carbon atoms overlap side by side to form a pi bond between carbon atoms.

The chemical formula for ethene is C2H4, which support a standard formula of CnH2n. In 1864, it was discovered that gas leaks from street lights led to stunting of growth, twisting of plants, and abnormal thickening of stems. In 1901, a Russian scientist named Dimitry Neljubow showed that the active component was ethene. Ethene is highly flammable and burn readily in air, forming carbon dioxide and water. The meltig point of ethene is -169 ^oC and boiling point is -103 ^oC. Because of the presence of the double bond in ethene, it is very reactive and readily forms many products such as chloroethane, bromoethane etc.

Uses of Ethane:

Ethylene is involved in the natural process of fruit ripening. Ethene is also known as "ripening hormone" as it's used as a plant hormone to control the ripening and color development of fruit. The ethylene produced by ripened is a gas and can move to other fruits to stimulating their ripening. In commercial situations, ripening can either be sped up (by storing fruit in containers with high ethylene content) or slowed down (by storing them in bins periodically flushed with carbon dioxide to prevent ethylene build up and inhibit further ethylene synthesis). Many commercial fruit producers will alter the rate of ripening. To speed up the process, they can store unripened fruit in containers with high amounts of ethylene gas. To prevent or slow down ripening, carbon dioxide can be used as an ethylene trap.  This not only keeps ethylene levels low but also prevents new ethylene production.

Ethane is also use to prepare plastics. For the preparation of plastic ethene is polymerized. Polymerization is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. Ethene is used in the manufacture of many important polymers like polyethene and polyvinyl chloride (PVC). These polymers are used in the manufacture of raincoats, shoe soles, pipes and floor tiles.

Ethanol is prepared from Ethene which is used in antiseptic and some antibacterial soaps and wipes. Ethanol is effective against viruses, fungi and most bacteria but is ineffective against bacterial spores. Ethylene is used in the production of specialty glass for the automotive industry (car glass).  Ethylene is used as oxy-fuel gas in the metal cutting, welding and High Velocity Thermal Spraying.

Ethylene is used as refrigerant, especially in LNG liquefaction plants. It is also used in the extraction of rubber. Ethylene glycol (C2H6O2) which is prepared from Ethene is used as antifreeze in cooling and heating systems, in hydraulic brake fluids, as an industrial humectant, as an ingredient of electrolytic condensers, as a solvent in the paint and plastics industries and in many other things. Ethylene glycol is also used to de-ice airport runways and aircraft. Ethene is a petroleum gas that is useful as industrial gas. 

Why onion makes you cry?!

Onion is one of the oldest vegetables known to human being.It’s an abundant source of nutrients, including vitamins B, C and G, protein, starch as well as compounds which have been said to be effective agents against fungal and bacterial growth; protecting against various cancers. In addition to that, it is used in a wide array of food preparations and recipes to add a specific flavor. Unless you've avoided cooking, you've probably cut up an onion and experienced the burning and tearing you get from the vapors. When you cut an onion, you break cells, releasing their contents. Amino acid sulfoxides form sulfenic acids. 

A sulfenic acid is an organosulfur compound and oxoacid with the general formula RSOH, where R ≠ H. It is the first member of the family of organosulfur oxoacids, which also include sulfinic acids and sulfonic acids, RSO2H and RSO3H, respectively. Sulfenic acids are produced by the enzymatic decomposition of alliin and related compounds following tissue damage to garlic, onions, and other plants of the Allium genus.

Cooking the onion inactivates the enzyme, so while the smell of cooked onions may be strong, it doesn't burn your eyes. Aside from wearing safety goggles or running a fan, you can keep from crying by refrigerating your onion before cutting it (slows reactions and changes the chemistry inside the onion) or by cutting the onion under water. The sulfur-containing compounds also leave a characteristic odor on your fingers. You may be able to remove or reduce some of the smell by wiping.

Or just a simple solution is to keep your head as far away from the onion as possible.

Onion possesses some medicinal properties, offering several health benefits. Onion is found to be effective to treat the medical conditions such as cold, diabetes, heart disease, osteoporosis and other diseases. They contain the chemicals that are believed to have anti-cholesterol, anti-inflammatory, antioxidants and anticancer properties.

Citric Acid

Citric Acid

Citric acid is a weak organic acid. It is naturally found in citrus fruits. It easily mixes into liquids, making it a valuable acid. Lemons and limes have high concentrations of citric acid, accounting for their bitter taste. Oranges and tangerines are also high in citric acid, though lower than the more bitter citrus fruits. Citric acid can be added to ice cream as an emulsifying agent to keep fats from separating, to caramel to prevent sucrose crystallisation, or to recipes in place of fresh lemon juice.

Citric acid is used as a flavouring in many preparations of Vitamin C, and has a wide variety of other uses. In industry, citric acid can be used to make good “natural” cleaners. It is used to soften water. Citric acid is the active ingredient in some bathroom and kitchen cleaning solutions.

Citric acid is a normal component of human cells that is metabolised, degraded, and eliminated from the body. Also known as E330, it is one of the main ingredients in the food and beverage industry because it is easily obtained in large quantities, healthy and cheap. It is often used for proper mineral supplementation of food, as an acidity regulator, and as a flavor compound. Citric acid enhances the activity of many beneficial antioxidants, but is not, itself, an antioxidant.

Citric acid was first artificially produced in 1784 from lemon juice, by Karl Wilhelm Scheele. It is the most frequently used preservative in the world today. Citric acid also prevents the formation of kidney stones and ensures proper functioning of the kidneys. Citric acid's ability to chelate calcium and its alkalising properties make it useful as a method for preventing kidney stones. In the case of stained skin or freckles, the use of a cream rich in citric acid will have a depigmentation effect. Citric acid is known to have the ability to destroy bacteria, mold, viruses and rust, and therefore was used in the production of pesticides, fungicides and disinfectants solutions. It is used in the manufacture of medicinal products and in bio-technology industries. It is combined with sodium bicarbonate for medicines such as Alka-Seltzer.