If 0.208g of an unknown salt of oxalate ion requires 25mL of 0.02 M MnO4^- solution, calculate the molar mass and write the molecular formula of the unknown ( oxalare is the anion, what is the cation?).
Write the equation between oxalate and permanganate and balance it.
Calculate mols MnO4^- = M x L = ?
Using the coefficients in the balancaed equation, convert mols MnO4^- to mols C2O4^2-.
Then mols = grams/molar mass
You have mols and grams, solve for molar mass. Then subtract the molar mass of the oxalate from the total molar mass to determine the mass of the cation and you can make an educated guess as to the name of the cation.