Question

A 100ml sample of hard water is titrated with the edta solution in problem 2. The same amount of Mg₂⁺+ is added and the volume of EDTA required is 21.15ml. What is the concentration of Mg₂⁺+ in the hard water sample?

Answer 1

To calculate the concentration of NaCl in the solution, we need to use the stoichiometry of the reaction between AgNO3 and NaCl. By determining the number of moles of AgNO3 used in the titration and using the stoichiometry, we can find the number of moles of NaCl in the solution. Finally, the concentration of NaCl can be calculated by dividing the moles of NaCl by the volume of the solution.

Step-by-step explanation:

The concentration of NaCl in the solution can be calculated using the stoichiometry of the reaction between AgNO3 and NaCl. From the balanced equation, we can see that one mole of AgNO3 reacts with one mole of NaCl. Therefore, the number of moles of AgNO3 used in the titration is equal to the number of moles of NaCl in the solution.

Given the volume and molarity of AgNO3 used in the titration, we can calculate the number of moles of AgNO3 used. Then, using the stoichiometry of the reaction, we can determine the number of moles of NaCl in the solution. Finally, the concentration of NaCl can be expressed as moles per liter.

Here is the calculation:

1. Calculate the number of moles of AgNO3 used: moles of AgNO3 = volume of AgNO3 solution (L) × molarity of AgNO3 (M)
2. Convert moles of AgNO3 to moles of NaCl using the stoichiometry: moles of NaCl = moles of AgNO3
3. Calculate the concentration of NaCl: concentration of NaCl (M) = moles of NaCl / volume of solution (L)