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However, general purpose computer programs that are used to derive equilibrium constant values from experimental data use association constants for both acids and bases. Because stability constants for a metal-ligand complex are always specified as association constants, ligand protonation must also be specified as an association reaction. [17]
The position of equilibrium varies from base to base when a weak base reacts with water. The further to the left it is, the weaker the base. [5] When there is a hydrogen ion gradient between two sides of the biological membrane, the concentration of some weak bases are focused on only one side of the membrane. [6]
Strong acids, such as sulfuric or phosphoric acid, have large dissociation constants; weak acids, such as acetic acid, have small dissociation constants. The symbol K a , used for the acid dissociation constant, can lead to confusion with the association constant , and it may be necessary to see the reaction or the equilibrium expression to ...
The self-ionization of water can be ignored. This assumption is not, strictly speaking, valid with pH values close to 7, half the value of pK w, the constant for self-ionization of water. In this case the mass-balance equation for hydrogen should be extended to take account of the self-ionization of water.
The higher the percentage, the stronger the electrolyte. Thus, even if a substance is not very soluble, but does dissociate completely into ions, the substance is defined as a strong electrolyte. Similar logic applies to a weak electrolyte. Strong acids and bases are good examples, such as HCl and H 2 SO 4. These will all exist as ions in an ...
Stronger acids have a larger and a smaller logarithmic constant (= ) than weaker acids. The stronger an acid is, the more easily it loses a proton, H + {\displaystyle {\ce {H+}}} . Two key factors that contribute to the ease of deprotonation are the polarity of the H − A {\displaystyle {\ce {H-A}}} bond and the size of atom A, which ...
However, for weak acids, a quadratic equation must be solved, and for weak bases, a cubic equation is required. In general, a set of non-linear simultaneous equations must be solved. Water itself is a weak acid and a weak base, so its dissociation must be taken into account at high pH and low solute concentration (see Amphoterism).
where pK a is the dissociation constant of BH +. They were originally measured by using nitroanilines as weak bases or acid-base indicators and by measuring the concentrations of the protonated and unprotonated forms with UV-visible spectroscopy. [3] Other spectroscopic methods, such as NMR, may also be used.