Ionic Strength and Activity Coefficient Calculation in Chemistry

How to calculate the ionic strength of a solution?

Given data: We have a solution that is 0.0003 M in Na3PO4 and 0.0002 molar in K3PO4. Calculate the ionic strength of the solution.

Calculation of Ionic Strength:

To calculate the ionic strength of the solution, we need to determine the contribution of each ion in the solution:

For Na3PO4:

- Na+ has a charge of +1 and a concentration of 0.0003 M.

- PO3- has a charge of -3 and a concentration of 0.0003 M.

Contribution of Na+: (0.0003 M) * (1) = 0.0003

Contribution of PO3-: (0.0003 M) * (-3) = 0.0009

For K3PO4:

- K+ has a charge of +1 and a concentration of 0.0002 M.

- PO3- has a charge of -3 and a concentration of 0.0002 M.

Contribution of K+: (0.0002 M) * (1) = 0.0002

Contribution of PO3-: (0.0002 M) * (-3) = 0.0006

Summing up the contributions:

Ionic strength = 0.0003 + 0.0009 + 0.0002 + 0.0006 = 0.0018