What is the percent dissociation of a 0.55 M solution of weak acid HC3H5O3 (Ka = 1.4 × 10−4)?

Explanation:

Percent dissociation is the amount of the substance dissociated per 100 parts.

Determine how much dissociate from a 0.55 M solution.

1. Write the dissociation equation:

          C₃H₅O₃H ⇄ C₃H₅O₃H⁻ + H⁺

2. Build the ICE (initial, change, equilibrium) table:

        C₃H₅O₃H ⇄ C₃H₅O₃H⁻ + H⁺

I          0.55M             0              0

C           - x                 +x             +x

E         0.55 - x            x              x

3. Write the equilibrium equation and calculate x

   Use the quadratic equation:

The positve value is x = 0.0087

4. Calculate the percent dissociation, α