Question

The formate ion, (CHO₂^-), is related to the acetate ion and forms ionic salts with many metal ions. Assume that 11.874 g of M(CHO₂)₂ (where M represents the atomic symbol for a particular metal) are dissolved in water. When a solution of 0.300 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 12.115 g. The filtrate is placed aside.

A potassium permanganate solution is standardized by dissolving 1.0734 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 21.50 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 300-mL volumetric flask, diluting to the mark with water, then mixing thoroughly. Then 15.00 mL of this diluted solution is pipetted into a 125-mL Erlenmeyer flask, approximately 35 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.

Answer 1

The redox equation is:

Now, calculate the moles of permanganate used to neutralizes the sodium oxalate

Now, calcluate the concentration of permanganate solution:

The normality is:

Now, write the redox equation between permanganate and formiate ions:

Now, we need to know the final concentration of formiate:

Now, we can calculate the volume needed of permanganate.

There is some missing data. You need to know the molecular weight of M(CHO2)2 or the concentration 1.