The Acid Dissociation Constant Ka (OCR A-Level Chemistry A): Flashcards

Complete dissociation

Partial dissociation, establishes equilibrium

$K_a = \frac{[\text{H}^+][\text{A}^-]}{[\text{HA}]}$

mol dm$^{-3}$

Stronger acid, more dissociation

$\text{pK}_a = -\log K_a$

$K_a = 10^{-\text{pK}_a}$

Stronger acid (inverse to $K_a$)

Sequential steps, each with own $K_a$

Removing H$^+$ from negative ion needs more energy