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The chemistry of calcium is that of a typical heavy alkaline earth metal. For example, calcium spontaneously reacts with water more quickly than magnesium and less quickly than strontium to produce calcium hydroxide and hydrogen gas. It also reacts with the oxygen and nitrogen in air to form a mixture of calcium oxide and calcium nitride. [14]
Calcium hydroxide has a high enough pH to turn the phenolphthalein a vivid purplish-pink color, thus indicating the presence of water. Chemical pulping: Calcium oxide is used to make calcium hydroxide, which is used to regenerate sodium hydroxide from sodium carbonate in the chemical recovery at kraft pulp mills.
However, if a metal reacts with steam, like magnesium, metal oxide is produced as a result of metal hydroxides splitting upon heating. [12] The hydroxides of calcium, strontium and barium are only slightly water-soluble but produce sufficient hydroxide ions to make the environment basic, giving a general equation of:
Calcium hypochlorite can also be used in the haloform reaction to manufacture chloroform. [8] Calcium hypochlorite can be used to oxidize thiol and sulfide byproducts in organic synthesis and thereby reduce their odour and make them safe to dispose of. [9] The reagent used in organic chemistry is similar to the sanitizer at ~70% purity. [10]
Solid calcium bromide adopts the rutile structure, featuring octahedral Ca 2+ centres bound to six bromide anions, which also bridge to other Ca 2+ centres. When strongly heated in air, calcium bromide reacts with oxygen to produce calcium oxide and bromine: 2 CaBr 2 + O 2 → 2 CaO + 2 Br 2
Other important organic compounds that contain oxygen are: glycerol, formaldehyde, glutaraldehyde, citric acid, acetic anhydride, acetamide, etc. Epoxides are ethers in which the oxygen atom is part of a ring of three atoms. Oxygen reacts spontaneously with many organic compounds at or below room temperature in a process called autoxidation. [7]
In the making of calcium oxide, calcium carbonate (limestone) breaks down upon heating, releasing carbon dioxide: [2] + The reaction of elements with oxygen in air is a key step in corrosion relevant to the commercial use of iron especially. Almost all elements form oxides upon heating with oxygen atmosphere.
The reaction of calcium carbide with water, producing acetylene and calcium hydroxide, [5] was discovered by Friedrich Wöhler in 1862. CaC 2 + 2H 2 O → C 2 H 2 + Ca(OH) 2 (aq) This reaction was the basis of the industrial manufacture of acetylene, and is the major industrial use of calcium carbide.