The pH of Weak Acids (OCR A-Level Chemistry A): Quizzes

They only partially dissociate

An equilibrium

They are formed in equal quantities

$K_\text{a} = \frac{[\text{H}^+]^2}{[\text{HA}]}$

$[\text{H}^+] = \sqrt{K_\text{a} \times [\text{HA}]}$

When pH is greater than 6

When $K_\text{a} > 10^{-2}$ mol dm$^{-3}$

$10^{-7}$ mol dm$^{-3}$

Prepare standard solution and measure pH

$[\text{H}^+] = 10^{-\text{pH}}$