What does pka and pkb mean

In other words, the equilibrium constants indicate acid and base strength and describe the level of ionization of an acid or a base. Like pH, the pKa and Ka values account for hydrogen ion concentration. Like pOH, the pKb and Kb values account for hydroxide ion concentration. When dealing with equilibrium constant, remember adding water to an aqueous acid or base solution does not change its equilibrium constant.

A pH value around 7 is neutral neither acidic nor basic , a pH value less than 7 is acidic, and a pH value greater than 7 is basic. Ka is the acid dissociation constant. A large Ka value indicates a strong acid because it means an acid largely dissociates into its ions. A large Ka value also means the reaction arrow favors the formation of production. In contrast, a small Ka value means only a small amount of acid dissociates, indicating a weak acid.

Two species that differ by only a proton constitute a conjugate acid—base pair. For an aqueous solution of a weak acid, the dissociation constant is called the acid ionization constant Ka. Similarly, the equilibrium constant for the reaction of a weak base with water is the base ionization constant Kb.

Acid—base reactions always proceed in the direction that produces the weaker acid—base pair. Chem1 Virtual Textbook. Butyric acid is responsible for the foul smell of rancid butter. Summary Two species that differ by only a proton constitute a conjugate acid—base pair. When a base is dissolved in water, it dissociates into ions forming a basic solution.

Strong bases dissociate completely. Weak bases dissociate partially. Since most of the Kb values are very large or very small, negative logarithms of these values are used to make it easy to deal with.

Therefore, a large Kb value can be characterized by a small pKb value with small decimal places. The difference between pKa and pKb is that pKa is the negative logarithm of Ka whereas pKb is the negative logarithm of Kb.

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