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When the acidic medium in question is a dilute aqueous solution, the is approximately equal to the pH value, which is a negative logarithm of the concentration of aqueous + in solution. The pH of a simple solution of an acid in water is determined by both K a {\displaystyle K_{{\ce {a}}}} and the acid concentration.
Express each concentration value as the ratio c/c 0, where c 0 is the concentration in a [hypothetical] standard state, with a numerical value of 1, by definition. [19] Express the concentrations on the mole fraction scale. Since mole fraction has no dimension, the quotient of concentrations will, by definition, be a pure number.
Using these values and the equality conditions, the concentrations of the three species, chromate CrO 2− 4, hydrogen chromate HCrO − 4 and dichromate Cr 2 O 2− 7 can be calculated, for various values of pH, by means of the equilibrium expressions. The chromium concentration is calculated as the sum of the species' concentrations in terms ...
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 called a "2 normal" solution. It can also be called a "2 normal" solution. Similarly, for a solution with c (H 3 PO 4 ) = 1 mol/L, the normality is 3 N because phosphoric acid contains 3 acidic H atoms.
The concentration of water, [H 2 O], is omitted by convention, which means that the value of K w differs from the value of K eq that would be computed using that concentration. The value of K w varies with temperature, as shown in the table below. This variation must be taken into account when making precise measurements of quantities such as pH.
The charge of a molecule depends upon the pH of its solution. In an acidic medium, basic drugs are more charged and acidic drugs are less charged. The converse is true in a basic medium. For example, Naproxen is a non-steroidal anti-inflammatory drug that is a weak acid (its pKa value is 5.0). The gastric juice has a pH of 2.0. It is a three ...
The values commonly given for pK a aq (H 3 O +) are 0 or –1.74. The former uses the convention that the activity of the solvent in a dilute solution (in this case, water) is 1, while the latter uses the value of the concentration of water in the pure liquid of 55.5 M. Silverstein has shown that the latter value is thermodynamically ...
The value H 0 = -12 for pure sulfuric acid must not be interpreted as pH = −12 (which would imply an impossibly high H 3 O + concentration of 10 +12 mol/L in ideal solution). Instead it means that the acid species present (H 3 SO 4 +) has a protonating ability equivalent to H 3 O + at a fictitious (ideal) concentration of 10 12 mol/L, as ...