The formate ion, (CHO2-), is related to the acetate ion and forms ionic salts with many metal ions. Assume that 9.7416 g of M(CHO2)2 (where M represents the atomic symbol for a particular metal) are dissolved in water. When a solution of 0.200 M sodium sulfate is added, a white precipitate forms. The sodium sulfate solution is added until no more precipitate forms, then a few excess milliliters are added. The precipitate is filtered, washed, and dried. It has a mass of 9.9389 g. The filtrate is placed aside.
A potassium permanganate solution is standardized by dissolving 0.9234 g of sodium oxalate in dilute sulfuric acid, which is then titrated with the potassium permanganate solution. The principal products of the reaction are manganese(II) ion and carbon dioxide gas. It requires 18.55 mL of the potassium permanganate solution to reach the end point, which is characterized by the first permanent, but barely perceptible, pink (purple) color of the permanganate ion.
The filtrate from the original reaction is diluted by pouring all of it into a 250-mL volumetric flask, diluting to the mark with water, then mixing thoroughly. Then 10.00 mL of this diluted solution is pipetted into a 125-mL Erlenmeyer flask, approximately 25 mL of water is added, and the solution is made basic. What volume of the standard permanganate solution will be needed to titrate this solution to the end point? The principal products of the reaction are carbonate ion and manganese(IV) oxide.
I already figured out the first part that M= Pb and I think I got the second part that KMnO4 molarity= .1793693, but I'm completely lost on part three. Any help is appreciated.
If I read the problem right the third part titrates the formate ion from part 1. Write the equation for formate + KMnO4 in basic solution.
2. You know how many mols formate from part 1. Convert that to mols MnO4^- in part 3.
3. Convert mols in part 3 for the dilution.
4. Then M KMnO4 = mols KMnO4/L KMnO4. You know mols and M, solve for L and convert to mL.
CHO2^- + KMnO4 > CO3^2- + MnO2
How are you supposed to balance the equations since there is no K in the products?
To determine the volume of the standard permanganate solution needed to titrate the solution in the third part, we need to use stoichiometry and the balanced equation of the reaction between permanganate and carbonate.
The balanced equation for the reaction is:
2MnO4- + 5C2O4^2- + 16H+ -> 2MnO2 + 10CO2 + 8H2O
From the balanced equation, we can see that the stoichiometric ratio between permanganate and carbonate is 2:5. This means that 2 moles of permanganate react with 5 moles of carbonate.
First, we need to calculate the number of moles of carbonate in the 10.00 mL solution pipetted into the Erlenmeyer flask.
Given:
Volume of the standard permanganate solution used = 18.55 mL
Molarity of the standard permanganate solution = 0.1793693 M
Using the formula:
moles = volume (L) x concentration (M)
moles of permanganate = (18.55 mL / 1000 mL/L) x 0.1793693 M
moles of permanganate = 0.00332208 moles
Since the stoichiometric ratio between permanganate and carbonate is 2:5, we can determine the moles of carbonate reacting with permanganate using the ratio:
moles of carbonate = (5/2) x moles of permanganate
moles of carbonate = (5/2) x 0.00332208 moles
moles of carbonate = 0.0083052 moles
Next, we need to calculate the concentration of the diluted filtrate in the 125-mL Erlenmeyer flask.
Given:
Volume of the diluted solution in the flask = 10.00 mL
Using the formula:
concentration = moles / volume (L)
concentration of carbonate = 0.0083052 moles / (10.00 mL / 1000 mL/L)
concentration of carbonate = 0.83052 M
Now that we have the concentration of carbonate in the 10.00 mL solution, we can determine the volume of the standard permanganate solution needed to react with all the carbonate.
Using the formula:
moles = concentration x volume (L)
moles of permanganate = 0.83052 M x (volume of permanganate solution / 1000 mL/L)
Rearranging the formula:
volume of permanganate solution = (moles of permanganate / concentration) x 1000 mL
Substituting the known values:
volume of permanganate solution = (0.0083052 moles / 0.1793693 M) x 1000 mL
volume of permanganate solution = 46.257 mL
Therefore, the volume of the standard permanganate solution needed to titrate the solution in the 125-mL Erlenmeyer flask to the end point is 46.257 mL.