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Sulfuric Acid 98%
Purified sulphuric acid manufactured by various filteration process by unique features.
Pure sulfuric acid has a specific gravity of 1.830 at 25° C (77° F); it freezes at 10.37° C (50.7° F). When heated, the pure acid partially decomposes into water and sulfur trioxide; the latter escapes as a vapour until the concentration of the acid falls to 98.3 percent. This mixture of sulfuric acid and water boils at a constant temperature of 338° C (640° F) at one atmosphere pressure. Sulfuric acid is commonly supplied at concentrations of 78, 93, or 98 percent.
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CAS Number of Sulfuric Acid 7664-93-9
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Linear Formula of Sulfuric Acid H2SO4
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Molecular Weight of Sulfuric Acid 98.08
When concentrated Sulfuric Acid and water are mixed, a tremendous amount of heat is released due to ionization of the acid. For instance, adding 1 volume of concentrated Sulfuric Acid to an equal volume of water (both at 25°C) results in a temperature rise to over 135°C. Therefore, the acid should always be diluted by adding it to the water. If the water is added to the acid, spattering could result which creates a hazardous situation and the possibility for severe chemical burns. The use of a 1 + 1 dilution of Sulfuric Acid with water (50% Sulfuric Acid, Group No. 8180) offers a much safer alternative in many instances when the use of Sulfuric Acid is required. For example, when 1 volume of concentrated Sulfuric Acid is added to 3 volumes of water, the temperature rises from 25°C to over 90°C. When the same solution is made by diluting 1 volume of 50% Sulfuric Acid with 1 volume of water, the temperature rises to less than 50°C.
When both acid and base are 1 Normal in concentration, indicators with effective ranges between pH 3 and 10.5 can be used. Suitable indicators include Methyl Orange, Bromocresol Green, Methyl Red, Methyl Purple, Bromothymol Blue, Phenol Red, Phenolphthalein and Thymolphthalein. When both the acid and base are 0.1 Normal, the ideal pH range is reduced to 4.5 to 9.5. Thus, Methyl Orange and Thymolphthalein are not as suitable as the others. With 0.01 Normal solutions, the ideal pH range is further limited to 5.5 - 8.5. See the indicator list and pH chart in the back of this catalog for details on suitable ranges for various indicators.
A basimetric standard such as Tris(hydroxymethyl)aminomethane can also be used to standardize Sulfuric Acid solutions. Methyl Red is a suitable indicator.