By A.P. Mentzer | Updated August 30, 2022
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Baking soda, chemically known as sodium bicarbonate (NaHCO₃), is a household staple and a versatile compound in scientific laboratories. Its measurable physical and chemical characteristics make it a textbook example of how matter behaves under different conditions.
Sodium bicarbonate consists of one sodium (Na), one carbon (C), one hydrogen (H) and three oxygen (O) atoms, giving it the formula NaHCO₃ or CHNaO₃. By weight, the compound is 57.1 % sodium, 27.4 % oxygen, 14.3 % carbon and 1.2 % hydrogen.
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The substance appears as a white, crystalline powder that sometimes clumps into small lumps. It is odorless and imparts a mildly bitter, salty flavor. At room temperature, sodium bicarbonate is a solid. Its solubility is a key physical property: it dissolves readily in water and can be recovered by simple evaporation.
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Key chemical behaviors include its alkalinity and thermal decomposition. A 1 % molar solution of baking soda in water has a pH of 8.3, placing it firmly in the alkaline range and explaining its bitter taste. When heated above 50 °C (122 °F), sodium bicarbonate decomposes into carbon dioxide (CO₂), water (H₂O), and a small amount of sodium carbonate (Na₂CO₃), a process that releases gas and is used in leavening applications.
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The alkaline nature of baking soda allows it to neutralize acids, making it effective for cleaning, deodorizing, and baking. Its mild abrasiveness also makes it suitable for gentle scrubbing, such as cleaning teeth or removing stains from surfaces.
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