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Sodium bicarbonate (IUPAC name: sodium hydrogencarbonate [9]), commonly known as baking soda or bicarbonate of soda, is a chemical compound with the formula NaHCO 3. It is a salt composed of a sodium cation (Na +) and a bicarbonate anion (HCO 3 −). Sodium bicarbonate is a white solid that is crystalline but often appears as a
1 H hydrogen (H 2) use: ... 11 Na sodium; use: 370.944 K: 97.794 °C ... The Gmelin rare earths handbook lists 1522 °C and 1550 °C as two melting points given in ...
Sodium carbonate serves as a flux for silica (SiO 2, melting point 1,713 °C), lowering the melting point of the mixture to something achievable without special materials. This "soda glass" is mildly water-soluble, so some calcium carbonate is added to the melt mixture to make the glass insoluble.
The bicarbonate ion (hydrogencarbonate ion) is an anion with the empirical formula HCO − 3 and a molecular mass of 61.01 daltons; it consists of one central carbon atom surrounded by three oxygen atoms in a trigonal planar arrangement, with a hydrogen atom attached to one of the oxygens.
It is manufactured by treating an aqueous solution of potassium carbonate or potassium hydroxide with carbon dioxide: [1] K 2 CO 3 + CO 2 + H 2 O → 2 KHCO 3. Decomposition of the bicarbonate occurs between 100 and 120 °C (212 and 248 °F): 2 KHCO 3 → K 2 CO 3 + CO 2 + H 2 O. This reaction is employed to prepare high purity potassium carbonate.
Inorganic compounds with simple ions typically have small ions, and thus have high melting points, so are solids at room temperature. Some substances with larger ions, however, have a melting point below or near room temperature (often defined as up to 100 °C), and are termed ionic liquids. [64]
Sodium is now produced commercially through the electrolysis of molten sodium chloride (common salt), based on a process patented in 1924. [64] [65] This is done in a Downs cell in which the NaCl is mixed with calcium chloride to lower the melting point below 700 °C. [66]
Sodium silicates can also be obtained by dissolving silica SiO 2 (whose melting point is 1713 °C) in molten sodium carbonate (that melts with decomposition at 851 °C): [17] x Na 2 CO 3 + SiO 2 → (Na 2 O) x · SiO 2 + CO 2. The material can be obtained also from sodium sulfate (melting point 884 °C) with carbon as a reducing agent: 2x Na 2 ...