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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:
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]
Citric acid is an organic compound with the formula H O C(CO 2 H)(CH 2 CO 2 H) 2. [10] It is a colorless weak organic acid. [10] It occurs naturally in citrus fruits.In biochemistry, it is an intermediate in the citric acid cycle, which occurs in the metabolism of all aerobic organisms.
McIlvaine buffer is a buffer solution composed of citric acid and disodium hydrogen phosphate, also known as citrate-phosphate buffer.It was introduced in 1921 by the United States agronomist Theodore Clinton McIlvaine (1875–1959) from West Virginia University, and it can be prepared in pH 2.2 to 8 by mixing two stock solutions.
Outside the transition range the concentration of acid or conjugate base is less than 10 % and the colour of the major species dominates. Species concentrations calculated with the program HySS for a 10 mM solution of citric acid. pK a1 = 3.13, pK a2 = 4.76, pK a3 = 6.40. A weak acid may be defined as an acid with pK a greater than
Nitric acid, with a pK value of around −1.7, behaves as a strong acid in aqueous solutions with a pH greater than 1. [23] At lower pH values it behaves as a weak acid. pK a values for strong acids have been estimated by theoretical means. [24] For example, the pK a value of aqueous HCl has been estimated as −9.3.
Pure water has a pH of 7 at 25°C, meaning it is neutral. When an acid is dissolved in water, the pH will be less than 7, while a base, or alkali, will have a pH greater than 7. 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 ...
Many carboxylic acid: aldehyde redox reactions have a potential near this value 2 H + + 2 e − → H 2: −0.41 Non-zero value for the hydrogen potential because at pH = 7, [H +] = 10 −7 M and not 1 M as in the standard hydrogen electrode (SHE), and that: E red = -0.059 V × 7 = -0.41 V: NADP + + H + + 2e − → NADPH: −0.320 −0.370 The ...