Question

What is the concentration of free Mn2+ in a 0.03 M solution of MnY2- buffered at pH 9? Calculate the concentration of free Mn2+ in the solution if you dilute it by a factor of 10. Does this concentration go up, go down or stay the same? Give a chemical reason for your answer.

Answer 1

concentration of the solution, MnY₂ = 0.03 M

1 mole of MnY₂ gives one mole of Mn²⁺ and two moles of Y^-

concentration of free Mn⁺² = 0.03 M

On dilution, the concentration of MnY₂ becomes 0.003 M

therefore, Concentration of Mn²⁺ becomes 0.003 M

the concentration becomes lesser than the previous concentration since the dilution increases the total volume of the solution but the amount of Mn²⁺ remains the same, therefore the molarity becomes less. and here the concentration is in the terms of molarity.