Calculate the ionisation constant of 0.08 ~mol~ dm ⁻³ of a monobasic acid having pH =2

Step-by-step solution

Ionization constant calculation Given a monobasic acid solution with concentration C = 0.08 mol dm ⁻³ and pH = 2. The hydrogen ion concentration is determined from the definition: [ H ^+] = 10^ - pH = 10⁻² = 0.01 mol dm ⁻³ For the dissociation HA H ^+ + A ^- , the ionization constant is expressed as: K_a = [ H ^+][ A ^-] [ HA ] Using the equilibrium concentrations: [ H ^+] = [ A ^-] = 0.01 and applying the approximation [ HA ] C = 0.08 (commonly used when dissociation is small), we compute: K_a = (0.01)(0.01) 0.08