Question

Write a balanced equation and Ka expression for the Brønsted-Lowry acid H2AsO4− in water. (In the balanced equation, be sure to indicate the state of each species and any charge associated with it.)

Answer 1

Answer and Explanation:

The balanced equation for the dissociation of H₂AsO₄⁻ in water (aqueous medium= aq) is the following:

H₂AsO₄⁻ (aq) ⇆ H⁺(aq) + HAsO₄²⁻(aq)

The monovalent anion H₂AsO₄⁻ loses a proton (H⁺) and forms the divalent anion HAsO₄²⁻.

The equilibrium constant Ka is calculated is given by the relation between the concentrations of products and reactants as follows:

$Ka= \frac{(H^{+}) . (HAsO_{4}^{2-})   }{(H_{2}AsO_{4}^{-})   }$