Question

The answers to these two questions must be calculated accurately to at least three decimal places.

Use the Extended Debye-Hückel equation to calculate the activity coefficient of Fe²⁺ in a solution of ionic strength μ= 0.0056 M at 25 °C.
γ =

Now, determine a value for this same activity coefficient by linear interpolation from the values listed in Table 7-1, D.C. Harris, "Quantitative Chemical Analysis", 8th ed.
γ =

Answer 1

Formula: Logγ_± = 0.509*z * (μ)^1/2

Where 'z' is the charge on the ion = +2

i.e. Logγ_± = 0.509*2 * (0.0056)^1/2

i.e. Logγ_± = 0.0762

Therefore, γ_± = 1.192