To find the KMnO4 solution molarity, the number of moles from the NaOH titration are used, resulting in a KMnO4 solution molarity of 0.092 M.
The question involves a titration problem where oxalic acid (H2C2O4) is titrated first with sodium hydroxide (NaOH) and then with potassium permanganate (KMnO4). The goal is to find the molarity of the KMnO4 solution. Given that 10ml of H2C2O4 reacts completely with 7.5ml of 0.4M NaOH and 10ml of the same H2C2O4 solution requires 16.3ml of KMnO4, we can use the balanced equations to find the molarity of KMnO4.
First, using the titration with NaOH:
Number of moles of NaOH = Volume × Molarity = 0.0075 L × 0.4 mol/L = 0.003 moles
From the reaction equation, we know the molar ratio of NaOH to H2C2O4 is 2:1, thus the moles of H2C2O4 is half that of NaOH, which is 0.0015 moles.
Next, using the titration with KMnO4:
Moles of H2C2O4 = Moles of KMnO4 because they react in a 1:1 molar ratio.
Molarity of KMnO4 = Moles / Volume = 0.0015 moles / 0.0163 L = 0.09202 M (2 decimal places)
The molarity of the KMnO4 solution is therefore 0.092 M.