What is the ionic strength of a 2:1 electrolyte with a concentration of 0.100 M?

Question

Quizplus · Accepted Answer

Ionic strength (I) is given by the formula:

I = 1/2 * ∑ci * zi^2, where ∑ci is the sum of concentrations of all ions and zi is the charge on the ion.

For a 2:1 electrolyte like CaCl2, we can assume that the electrolyte dissociates into three ions in solution: one Ca2+ ion and two Cl- ions.

Therefore, the sum of concentrations is:

∑ci = [Ca2+] + 2[Cl-] = 0.100 + 2(0.100) = 0.300 M

The charge on Ca2+ is +2, and the charge on Cl- is -1. Plugging these values into the ionic strength formula, we get:

I = 1/2 * [(0.100)(2^2) + 2(0.100)(-1^2)] = 0.300 M

Therefore, the answer is C)0)300.

What Is the Ionic Strength of a 2:1 Electrolyte with a Concentration