Answer :
Final answer:
The dissociation constant (Ka) of acetic acid is 1.69 x 10⁻⁵, reflecting its weak acid nature with minimal dissociation into acetate and hydrogen ions in aqueous solutions.
Explanation:
The dissociation constant (Ka) of acetic acid at the given temperature is 1.69 x 10⁻⁵. This value indicates acetic acid is a relatively weak acid, compared with strong acids like sulfuric acid (Ka = 109) or hydrochloric acid (Ka = 107), that dissociate almost completely in water. The small value of Ka reflects that only a minor fraction of the acetic acid molecules dissociate into acetate ions (CH3COO−) and hydrogen ions (H+) in solution, leaving a significant amount of undissociated acetic acid present.
For example, in a 0.1 M solution of acetic acid, only about 0.1% of the molecules are dissociated at 25 °C. This equilibrium behavior illustrates the acidic strength of acetic acid and its propensity to exist primarily as undissociated molecules in an aqueous solution, with minimal formation of acetate and hydronium ions.
