Question

A solution is prepared by dissolving 36.7845 grams of disodium ethylenediaminetetraacetic acid dihydate in enough water to prepare .5000 liters of solution. What is the molar concentration of ethylenediminediacetic-diacetate in solution? What is the expected sodium ion concentration?

Answer 1

Answer: The molar concentration of ethylenediminediacetic-dihydrate and sodium ions in solution is 0.1976 M and 0.3952 M respectively.

Explanation:

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}}{\text{Molar mass of solute}\times \text{Volume of solution (in L)}}$

We are given:

Mass of solute (disodium ethylenediaminetetraacetic acid dihydate) = 36.7845 g

Molar mass of disodium ethylenediaminetetraacetic acid dihydate = 372.24 g/mol

Volume of solution = 0.5000 L

Putting values in above equation, we get:

$\text{Molarity of solution}=\frac{36.7845g}{372.24g/mol\times 0.5000L}\\\\\text{Molarity of solution}=0.1976M$

As, 1 mole of disodium ethylenediaminetetraacetic acid dihydate produces 2 moles of sodium ion and 1 mole of ethylenediminediacetic-dihydrate.

Concentration of ethylenediminediacetic-dihydrate in solution = $(1\times 0.1976)=0.1976M$

Concentration of sodium ions in solution = $(2\times 0.1976)=0.3952M$

Hence, the molar concentration of ethylenediminediacetic-dihydrate and sodium ions in solution is 0.1976 M and 0.3952 M respectively.