Acidic Strength - Definition of $$K_a$$ and $$pK_a$$

$$K_a = \frac{[\text{RCOO}^-][\text{H}^+]}{[\text{RCOOH}]} \quad \text{and} \quad pK_a = -\log_{10}(K_a)$$

Concept: Quantifies the ionization capability of a weak acid in an aqueous environment. The thermodynamic benchmark dictates that a higher equilibrium constant value or a lower negative logarithm scale corresponds to a significantly stronger acid.

Notation:

• $$K_a$$ = Acid dissociation constant;
• $$pK_a$$ = $$-log(K_a)$$
• $$\text{Higher } K_a / \text{Lower } pK_a \longrightarrow \text{Stronger Acid}$$