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The Henderson–Hasselbalch equation can be used to model these equilibria. It is important to maintain this pH of 7.4 to ensure enzymes are able to work optimally. [10] Life threatening Acidosis (a low blood pH resulting in nausea, headaches, and even coma, and convulsions) is due to a lack of functioning of enzymes at a low pH. [10]
The equations, derived from the acidity constant and basicity constant, states that when pH equals the pK a or pK b value of the indicator, both species are present in a 1:1 ratio. If pH is above the p K a or p K b value, the concentration of the conjugate base is greater than the concentration of the acid, and the color associated with the ...
After rearranging the expression defining the acid dissociation constant, and putting pH = −log 10 [H +], one obtains pH = pK a – log ( [AH]/[A −] ) This is a form of the Henderson-Hasselbalch equation. It can be deduced from this expression that when the acid is 1 % dissociated, that is, when [AH]/[A −] = 100, pH = pK a − 2
Published values for log K 1 and log K D are 5.89 and 2.05, respectively. [2] 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 ...
A strong acid, such as hydrochloric acid, at concentration 1 mol dm −3 has a pH of 0, while a strong alkali like sodium hydroxide, at the same concentration, has a pH of 14. Since pH is a logarithmic scale, a difference of one in pH is equivalent to a tenfold difference in hydrogen ion concentration.
The Charlot equation, named after Gaston Charlot, is used in analytical chemistry to relate the hydrogen ion concentration, and therefore the pH, with the formal analytical concentration of an acid and its conjugate base. It can be used for computing the pH of buffer solutions when the approximations of the Henderson–Hasselbalch equation ...
With specific values for C a and K a this quadratic equation can be solved for x. Assuming [4] that pH = −log 10 [H +] the pH can be calculated as pH = −log 10 x. If the degree of dissociation is quite small, C a ≫ x and the expression simplifies to = and pH = 1 / 2 (pK a − log C a).
For example, tens of thousands of industrially manufactured chemicals are in common use, but only a small fraction have undergone rigorous toxicological evaluation. Hence there is a need to prioritize the remainder for testing. QSAR equations, which in turn are based on calculated partition coefficients, can be used to provide toxicity estimates.