Search results
Results from the WOW.Com Content Network
Citric acid also dissolves in absolute (anhydrous) ethanol (76 parts of citric acid per 100 parts of ethanol) at 15 °C. It decomposes with loss of carbon dioxide above about 175 °C. Citric acid is a triprotic acid , with pK a values, extrapolated to zero ionic strength, of 3.128, 4.761, and 6.396 at 25 °C. [ 21 ]
When the difference between successive pK a values is less than about 3, there is overlap between the pH range of existence of the species in equilibrium. The smaller the difference, the more the overlap. 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.
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.
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
An individual chemical shift δ is the mole-fraction-weighted average of the shifts δ of nuclei in contributing species. ¯ = Example: the pK a of the hydroxyl group in citric acid has been determined from 13 C chemical shift data to be 14.4.
A mnemonic is a memory aid used to improve long-term memory and make the process of consolidation easier. Many chemistry aspects, rules, names of compounds, sequences of elements, their reactivity, etc., can be easily and efficiently memorized with the help of mnemonics.
Trisodium citrate is a chemical compound with the molecular formula Na 3 C 6 H 5 O 7. It is sometimes referred to simply as "sodium citrate", though sodium citrate can refer to any of the three sodium salts of citric acid. It possesses a saline, mildly tart taste, and is a mild alkali.
Acid strength is the tendency of an acid, symbolised by the chemical formula, to dissociate into a proton, +, and an anion, .The dissociation or ionization of a strong acid in solution is effectively complete, except in its most concentrated solutions.