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For example, concentrated sulfuric acid with a specific gravity of 1.8 has a Twaddell scale measurement of 160, reflecting the linear relationship between readings and specific gravity. The Twaddell scale is used exclusively for liquids with specific gravity greater than that of water.
The oleum is then diluted with water to form concentrated sulfuric acid. H 2 SO 4 + SO 3 → H 2 S 2 O 7 H 2 S 2 O 7 + H 2 O → 2 H 2 SO 4. Directly dissolving SO 3 in water, called the "wet sulfuric acid process", is rarely practiced because the reaction is extremely exothermic, resulting in a hot aerosol of sulfuric acid that requires ...
In the case of citric acid, the overlap is extensive and solutions of citric acid are buffered over the whole range of pH 2.5 to 7.5. Calculation of the pH with a polyprotic acid requires a speciation calculation to be performed. In the case of citric acid, this entails the solution of the two equations of mass balance:
Normality can be used for acid-base titrations. For example, sulfuric acid (H 2 SO 4) is a diprotic acid. Since only 0.5 mol of H 2 SO 4 are needed to neutralize 1 mol of OH −, the equivalence factor is: f eq (H 2 SO 4) = 0.5. If the concentration of a sulfuric acid solution is c(H 2 SO 4) = 1 mol/L, then its normality is 2 N. It can also be ...
The first and faster [citation needed] process is the removal of hydrogen and oxygen as units of water by the concentrated sulfuric acid. This occurs because hydration of concentrated sulfuric acid is strongly thermodynamically favorable, with a standard enthalpy of reaction of −880 kJ/mol.
From the above stoichiometric equations, we can find that: 1 mole of O 2 → 2 moles of MnO(OH) 2 → 2 mole of I 2 → 4 mole of S 2 O 2− 3. Therefore, after determining the number of moles of iodine produced, we can work out the number of moles of oxygen molecules present in the original water sample.
Acetic acid is said to be a differentiating solvent for the three acids, while water is not. [6]: (p. 217) An important example of a solvent which is more basic than water is dimethyl sulfoxide, DMSO, (). A compound which is a weak acid in water may become a strong acid in DMSO.
Sulfation is the chemical reaction that entails the addition of SO 3 group. In principle, many sulfations would involve reactions of sulfur trioxide (SO 3). In practice, most sulfations are effected less directly. Regardless of the mechanism, the installation of a sulfate-like group on a substrate leads to substantial changes.