Safety
Calcium hypochlorite is stored dry and cold, away from any acid, organic materials, and metals. The hydrated form is safer to handle.
If mixed with an acid it releases highly toxic chlorine gas.
A confusion sometimes reigns between calcium oxychlorides and calcium hypochlorite. Indeed, the name calcium oxychloride (or calcium hydroxychloride) does not immediately refer to calcium hypochlorite, but is only applicable to the mixed calcium basic chloride compounds remaining unreacted in the bleaching powder, such as, e.g. CaCl2 · 2 Ca(OH)2.
Calcium oxychloride may also be formed in concrete in roads and bridges when calcium chloride is used as deicing agent during winter. Calcium chloride then reacts with calcium hydroxide (portlandite) present in cement hydration products and forms a deleterious expanding phase also named CAOXY (abbreviation for calcium oxychloride) by concrete technologists. The stress induced into concrete by crystallisation pressure and CAOXY salt expansion can considerably reduce the strength of concrete.
Calcium hypochlorite exhibits both acido-basic and oxydo-reduction properties. It is a relatively strong base.
Calcium hypochlorite solution is basic as the hypochlorite anion can accept a proton from a water molecule leaving a hydroxyُl anion in solution. This basicity is due to the propensity for the hypochlorite anion to accept a proton to become hypochlorous acid, a weak acid:
The hypochlorite anion is also a strong oxidizing agent containing a chlorine atom at the valence I (redox state: Cl+1) which reacts under acidic conditions with the reduced chloride species (Cl–, here the reducing agent) present in hydrochloric acid to form calcium chloride, water and gaseous chlorine. The overall reaction is:
Calcium hypochlorite is stored dry and cold, away from any acid, organic materials, and metals. The hydrated form is safer to handle.
If mixed with an acid it releases highly toxic chlorine gas.
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Hydrogen peroxide is a chemical compound with the formula H2O In its pure form, it is a very pale blue liquid, slightly more viscous than water. Hydrogen peroxide is the simplest peroxide (a compound with an oxygen–oxygen single bond). It is used as an oxidizer, bleaching agent, and antiseptic. Concentrated hydrogen peroxide, or "high-test peroxide", is a reactive oxygen species and has been used as a propellant in rocketry.Its chemistry is dominated by the nature of its unstable peroxide bond.
Hydrogen peroxide is unstable and slowly decomposes in the presence of light. Because of its instability, hydrogen peroxide is typically stored with a stabilizer in a weakly acidic solution in a dark coloured bottle. Hydrogen peroxide is found in biological systems including the human body. Enzymes that use or decompose hydrogen peroxide are classified as peroxidases.
Alexander von Humboldt reported one of the first synthetic peroxides, barium peroxide, in 1799 as a by-product of his attempts to decompose air.
Nineteen years later Louis Jacques Thénard recognized that this compound could be used for the preparation of a previously unknown compound, which he described as eau oxygénée ("oxygenated water") – subsequently known as hydrogen peroxide.Today this term refers instead to water containing dissolved oxygen (O2).
The immersed hull and fittings of a ship at sea, particularly in coastal waters, are subject to algae, barnacle, mussel, and other shellfish growth that can impair its hydrodynamic performance and adversely affect the service of the immersed fittings.
Fittings such as cooling water intake systems are often protected by impressed current antifouling systems, and immersed hulls today are finished with very effective self-polishing antifouling paints.
The functional principle of these systems is the establishment of an artificially triggered voltage difference between copper anodes and the integrated steel plate cathodes. This causes a minor electrical current to flow from the copper anodes, so that they are dissolved to a certain degree. A control unit makes sure that the anodes add the required minimum amount of copper particles to the sea water, thus ensuring the formation of copper oxide that creates ambient conditions precluding local fouling. A control unit can be connected to the management system of the vessel. Using information from the management system, the impressed current antifouling system can determine the amount of copper that needs to be dissolved to give optimum performance with minimum wastage of the anodes.
Potassium carbonate is the inorganic compound with the formula K2CO3. It is a white salt, which is soluble in water. It is deliquescent, often appearing as a damp or wet solid. Potassium carbonate is mainly used in the production of soap and glass.
Potassium carbonate is the primary component of potash and the more refined pearl ash or salts of tartar. Historically, pearl ash was created by baking potash in a kiln to remove impurities. The fine, white powder remaining was the pearl ash. The first patent issued by the US Patent Office was awarded to Samuel Hopkins in 1790 for an improved method of making potash and pearl ash.
In late 18th century North America, before the development of baking powder, pearl ash was used as a leavening agent for quick breads.
Bleach is the generic name for any chemical product which is used industrially and domestically to remove color from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers, specifically, to a dilute solution of sodium hypochlorite, also called "liquid bleach".
Many bleaches have broad spectrum bactericidal properties, making them useful for disinfecting and sterilizing and are used in swimming pool sanitation to control bacteria, viruses, and algae and in many places where sterile conditions are required. They are also used in many industrial processes, notably in the bleaching of wood pulp. Bleaches also have other minor uses like removing mildew, killing weeds, and increasing the longevity of cut flowers.
Bleaches work by reacting with many colored organic compounds, such as natural pigments, and turning them into colorless ones. While most bleaches are oxidizing agents (chemicals that can remove electrons from other molecules), some are reducing agents (that donate electrons).
Chlorine, a powerful oxidizer, is the active agent in many household bleaches. Since pure chlorine is a toxic corrosive gas, these products usually contain hypochlorite which releases chlorine when needed. "Bleaching powder" usually means a formulation containing calcium hypochlorite.
A confusion sometimes reigns between calcium oxychlorides and calcium hypochlorite. Indeed, the name calcium oxychloride (or calcium hydroxychloride) does not immediately refer to calcium hypochlorite, but is only applicable to the mixed calcium basic chloride compounds remaining unreacted in the bleaching powder, such as, e.g. CaCl2 · 2 Ca(OH)2.
Calcium oxychloride may also be formed in concrete in roads and bridges when calcium chloride is used as deicing agent during winter. Calcium chloride then reacts with calcium hydroxide (portlandite) present in cement hydration products and forms a deleterious expanding phase also named CAOXY (abbreviation for calcium oxychloride) by concrete technologists. The stress induced into concrete by crystallisation pressure and CAOXY salt expansion can considerably reduce the strength of concrete.
Calcium hypochlorite exhibits both acido-basic and oxydo-reduction properties. It is a relatively strong base.
Calcium hypochlorite solution is basic as the hypochlorite anion can accept a proton from a water molecule leaving a hydroxyُl anion in solution. This basicity is due to the propensity for the hypochlorite anion to accept a proton to become hypochlorous acid, a weak acid:
The hypochlorite anion is also a strong oxidizing agent containing a chlorine atom at the valence I (redox state: Cl+1) which reacts under acidic conditions with the reduced chloride species (Cl–, here the reducing agent) present in hydrochloric acid to form calcium chloride, water and gaseous chlorine. The overall reaction is:
Iron(III) chloride is the inorganic compound with the formula (FeCl 3). Also called ferric chloride, it is a common compound of iron in the +3 oxidation state. The anhydrous compound is a crystalline solid with a melting point of 307.6 °C. The color depends on the viewing angle: by reflected light the crystals appear dark green, but by transmitted light they appear purple-red.
Anhydrous iron(III) chloride has the BiI3 structure, with octahedral Fe(III) centres interconnected by two-coordinate chloride ligands.
Iron(III) chloride has a relatively low melting point and boils at around 315 °C. The vapour consists of the dimer Fe 2Cl 6 (cf. aluminium chloride) which increasingly dissociates into the monomeric FeCl 3 (with D3h point group molecular symmetry) at higher temperature, in competition with its reversible decomposition to give iron(II) chloride and chlorine gas.
In addition to the anhydrous material, ferric chloride forms four hydrates. All forms of iron(III) chloride feature two or more chlorides as ligands, and three hydrates feature FeCl4−.
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