What is the approximate concentration of free Ni²⁺(aq) remaining at equilibrium in a solution prepared by mixing 5.0 mL of 0.10 M NiCl(aq) ₂ with 5.0 mL of 2.0 M NH₃(aq) ?
[The net formation constant for the hexamminenickel(II) ion is 5.5 × 10⁸.]

Question

Quizplus · Accepted Answer

The concentration of free Ni^2+ at equilibrium can be calculated using the formula for the formation constant (K_f) of the hexaamminenickel(II) ion, Ni(NH_3)_6^2+. Given K_f = 5.5 × 10^18, we can set up an equilibrium expression involving the concentrations of Ni^2+, NH_3, and the complex ion. Initially, the concentration of Ni^2+ is diluted due to mixing, as is the concentration of NH_3. The final concentration of Ni^2+ can be found by applying the stoichiometry of the reaction and the large value of K_f, which suggests that the reaction proceeds almost to completion, leaving a very small concentration of free Ni^2+. Calculations considering dilution and the equilibrium constant lead to the conclusion that option B is correct.

What Is the Approximate Concentration of Free Ni2+(aq)remaining at Equilibrium

What Is the Approximate Concentration of Free Ni²⁺(aq)remaining at Equilibrium