Common Chemical Compounds and Reactions

Hard water is caused by the presence of minerals mainly calcium and magnesium in it. The minerals get into the water if it passes through soft rocks like chalk or limestone. If water passes through hard rocks like granite or through peaty soils, it does not pick up these minerals therefore remains soft.

Calcium hydride was, in the 1940s, available under the trade name "Hydrolith" as a source of hydrogen:.

Since, Sb₂S₃ is an anionic sol. According to Hardy Schulze rule, greater the valency of cationic coagulating agent, greater its coagulating power. Therefore, Si(NO₃)₄ has most valency (+4), and hence it will be the most effective coagulation agent in the present case.

A recent development in detergent enzymes has been the introduction of an alkaline-stable fungal cellulase preparation for use in washing cotton fabrics. 

A standard dry cell (zinc-carbon battery) uses a paste of ammonium chloride as the electrolyte, which allows ion flow between the zinc anode and carbon cathode. Manganese dioxide is the cathode depolarizer, not the electrolyte.

Calcium ions (Ca2+) are essential cofactors in the blood coagulation cascade. They participate in multiple steps including activation of clotting factors and conversion of prothrombin to thrombin. Without calcium, the clotting process cannot proceed effectively. Sodium and potassium are involved in nerve conduction, and chloride is an electrolyte.

Ammonium acetate is a chemical compound with the formula CH₃COONH₄ (or C₂H₄O₂.NH₃ or C₂H₇NO₂). It is a white solid, which can be derived from the reaction of ammonia and acetic acid. It is used as a biodegradable de-icing agent.

Ammonium chloride is an inorganic compound with the formula NH₄Cl. It is a white crystalline salt that is highly soluble in water. Solutions of ammonium chloride are mildly acidic. It is used to produce low temperatures in cooling baths.

Ammonium bituminosulphonate is a product of natural origin obtained in the first step by dry distillation of sulphur-rich oil shale. It is used in medicine as a remedy for treating some skin diseases, such as acne, eczema and psoriasis.

Ammonium carbonate (NH₄)₂CO₃ is a commercial salt & used when crushed as a smelling salt. It can be crushed when needed in order to revive someone who has fainted. It is also known as baker's ammonia and was a predecessor to the more modern leavening agents like baking soda and baking powder.

Hirudin is the specific anticoagulant produced by the salivary glands of medicinal leeches (Hirudo medicinalis). It prevents blood clotting during feeding by inhibiting thrombin. Heparin is produced by mast cells in mammals, sodium citrate is an inorganic anticoagulant used in blood storage, and chelating agents are a broader category of compounds that bind metal ions.

Zeolites are aluminosilicate minerals that can exchange sodium ions for calcium and magnesium ions. This ion exchange process effectively removes permanent hardness caused by metal sulfates from water.

Washing soda is sodium carbonate decahydrate (Na2CO3·10H2O), used in laundry and cleaning. Calcium carbonate is limestone/chalk, calcium bicarbonate is found in hard water, and sodium bicarbonate is baking soda - these are distinct compounds with different uses.

Double salts are salts containing more than one cation or anion and are obtained by combination of two different salts which are crystallised in the same regular ionic lattice. For example: Mohr's salt.