Potassium permanganate (KMnO4) reacts with oxalic acid (H2C2O4) in aqueous sulfuric acid according to the follow-ing equation: How many milliliters of a 0.250 M KMnO4 solution are needed to react completely with 3.225 g of oxalic acid?

Verified step by step guidance

1. Write the balanced chemical equation for the reaction between potassium permanganate (KMnO_4) and oxalic acid (H_2C_2O_4) in acidic solution: \[ 2 \text{KMnO}_4 + 5 \text{H}_2\text{C}_2\text{O}_4 + 6 \text{H}_2\text{SO}_4 \rightarrow 2 \text{MnSO}_4 + 10 \text{CO}_2 + 8 \text{H}_2\text{O} + K_2\text{SO}_4 \]
2. Calculate the moles of oxalic acid (H_2C_2O_4) using its molar mass: \[ \text{Moles of } H_2C_2O_4 = \frac{\text{mass of } H_2C_2O_4}{\text{molar mass of } H_2C_2O_4} \]
3. Use the stoichiometry of the balanced equation to find the moles of KMnO_4 needed. According to the equation, 2 moles of KMnO_4 react with 5 moles of H_2C_2O_4. Therefore, \[ \text{Moles of KMnO}_4 = \frac{2}{5} \times \text{moles of } H_2C_2O_4 \]
4. Calculate the volume of the 0.250 M KMnO_4 solution required using the formula: \[ \text{Volume (L)} = \frac{\text{moles of KMnO}_4}{\text{molarity of KMnO}_4} \]
5. Convert the volume from liters to milliliters by multiplying by 1000.

Key Concepts

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between reactants and products in a chemical reaction. It allows us to calculate the amounts of substances consumed and produced in a reaction based on balanced chemical equations. Understanding stoichiometry is essential for determining how much of one reactant is needed to completely react with another.

Molarity

Molarity is a measure of concentration defined as the number of moles of solute per liter of solution. It is expressed in units of moles per liter (M). In this problem, the molarity of the KMnO4 solution is crucial for calculating how many moles of KMnO4 are present, which can then be used to find the volume needed to react with a given mass of oxalic acid.

Balancing Chemical Equations

Balancing chemical equations is the process of ensuring that the number of atoms for each element is the same on both sides of the equation. This is important because it reflects the conservation of mass in a chemical reaction. For this question, knowing the balanced equation for the reaction between potassium permanganate and oxalic acid is necessary to determine the stoichiometric ratios needed for the calculations.