Question

The number of moles of ${\mathrm{KMnO}}_4$ that will be needed to react completely with one mole of Ferrous Oxalate in acidic medium is:

• A. $\frac{2}{5}$
• B. $\frac{3}{5}$
• C. $\frac{4}{5}$
• D. $1$

Answer 1

The correct option is B

$\frac{3}{5}$

Explanation for the correct option:

[B]$\frac{3}{5}$

• We can find the number of ${\mathrm{KMnO}}_4$ moles needed to react completely with one mole of Ferrous Oxalate[${\mathrm{FeC}}_2{\mathrm{O}}_4$] in an acidic medium $=$ $\frac{3}{5}$by following the steps given:

Step 1: Writing the balanced chemical equation for the reaction:

• $3{\mathrm{KMnO}}_4+5{\mathrm{FeC}}_2{\mathrm{O}}_4+24{\mathrm{H}}^{+}\to 5{\mathrm{Fe}}^{3+}+10{\mathrm{CO}}_2+3{\mathrm{Mn}}^{2+}+3{\mathrm{k}}^{+}+12{\mathrm{H}}_2\mathrm{O}$

Step 2: Noting the moles of ${\mathrm{KMnO}}_4$ and ${\mathrm{FeC}}_2{\mathrm{O}}_4$ from the given equation:

• No. of ${\mathrm{KMnO}}_4$ moles required for the complete reaction$=3$
• No. of ${\mathrm{FeC}}_2{\mathrm{O}}_4$ moles required for the complete reaction$=5$

Step 3: Calculating the no. of ${\mathrm{KMnO}}_4$moles needed:

• $5\mathrm{mol}$of${\mathrm{FeC}}_2{\mathrm{O}}_4$ needs$3\mathrm{mol}$ ${\mathrm{KMnO}}_4$for a complete reaction to occur.
• Then, $1\mathrm{mol}$of${\mathrm{FeC}}_2{\mathrm{O}}_4$ needs$\frac{3}{5}$$\mathrm{mol}$ ${\mathrm{KMnO}}_4$for the complete reaction in an acidic medium.

So, option[B] is correct.

Explanation for the Incorrect option:

[A]$\frac{2}{5}$

• $5\mathrm{mol}$of${\mathrm{FeC}}_2{\mathrm{O}}_4$ needs$3\mathrm{mol}$ ${\mathrm{KMnO}}_4$for a complete reaction to occur.
• Then, $1\mathrm{mol}$of${\mathrm{FeC}}_2{\mathrm{O}}_4$ needs$\frac{3}{5}$$\mathrm{mol}$ ${\mathrm{KMnO}}_4$for the complete reaction in an acidic medium.

So, option[A] is Incorrect.

[C]$\frac{4}{5}$

• $5\mathrm{mol}$of${\mathrm{FeC}}_2{\mathrm{O}}_4$ needs$3\mathrm{mol}$ ${\mathrm{KMnO}}_4$for a complete reaction to occur.
• Then, $1\mathrm{mol}$of${\mathrm{FeC}}_2{\mathrm{O}}_4$ needs$\frac{3}{5}$$\mathrm{mol}$ ${\mathrm{KMnO}}_4$for the complete reaction in an acidic medium.

So, option[C] is Incorrect.

[D] $1$

• $5\mathrm{mol}$of${\mathrm{FeC}}_2{\mathrm{O}}_4$ needs$3\mathrm{mol}$ ${\mathrm{KMnO}}_4$for a complete reaction to occur.
• Then, $1\mathrm{mol}$of${\mathrm{FeC}}_2{\mathrm{O}}_4$ needs$\frac{3}{5}$$\mathrm{mol}$ ${\mathrm{KMnO}}_4$for a complete reaction in an acidic medium.

So, option[D] is Incorrect.

Hence, $\frac{3}{5}$$\mathrm{mol}$ ${\mathrm{KMnO}}_4$ is needed in an acidic medium for the reaction to occur completely.