Question

Volume of M/8 KMnO$_4$ solution required to react completely with 25.0 cm$^3$ of M/4 FeSO$_4$ in acidic medium is:

• A. 8.0 mL
• B. 5.0 mL
• C. 15.0 mL
• D. 10.0 mL

Hint:

In redox reactions involving KMnO$_4$ and FeSO$_4$, use the molarity equation to find the required volume of the reactants.

Answer 1

The Correct Option is D

Step 1: {Balance the Redox Reaction} 
The balanced ionic equation for the reaction is: \[ {MnO}_4^- + 5{Fe}^{2+} + 8{H}^+ \rightarrow {Mn}^{2+} + 5{Fe}^{3+} + 4{H}_2{O} \] Step 2: {Stoichiometric Relationship} 
From the equation, it is clear that 1 mole of KMnO$_4$ reacts with 5 moles of FeSO$_4$. 
Step 3: {Apply Molarity Equation} 
Use the molarity equation to balance the reaction: \[ \frac{M_1V_1}{n_1} \, ({KMnO}_4) = \frac{M_2V_2}{n_2} \, ({FeSO}_4) \] \[ \frac{1 \times V_1}{8 \times 1} = \frac{25 \times 5}{4 \times 5} \] Step 4: {Solve for \( V_1 \)} 
\[ V_1 = \frac{1 \times 25 \times 8}{4 \times 5} \] \[ V_1 = 10 { cm}^3 { or } V_1 = 10.0 { mL} \].