Question

A student determines that an aqueous solution that contains 0.196 M potassium fluoride and 0.206 M hydrofluoric acid, also has an H₃O⁺concentration of 8.48×10^-4 M. Based on these data, calculate the value of the equilibrium constant K for the equilibrium:

• HF(aq) + H₂O  H₃O⁺(aq) + F^-(aq)

Calculate K as is usually done, omitting the solvent, water, from the expression for K: K =

and

A student determines that an aqueous solution that contains 0.365 M potassium nitrite and 0.125 M nitrous acid, also has a H₃O⁺concentration of 2.10×10^-4 M. Based on these data, calculate the value of the equilibrium constant K for the equilibrium:

• HNO₂(aq) + H₂O  H₃O⁺(aq) + NO₂^-(aq)

(1) as is usually done, without the inclusion of water in the expression for K: K =

(2) for comparison, with the inclusion of water in the expression for K: K =

Answer 1