7. Which of the following solutions contains the greatest total ion concentration?

(A)One mole of potassium chloride dissolved in 1.0 L of solution.

(B)One mole of iron(II) nitrate dissolved in 1.0 L of solution.

(C)One mole of potassium hydroxide dissolved in 1.0 L of solution.

(D)One mole of sodium phosphate dissolved in 1.0 L of solution.

(E)At least two of the above solutions have an equal number of ions, and these contain the greatest total ion concentration.