Question

The number of moles of $ KMnO_{4}$ reduced by one mole of $KI$ in alkaline medium is

• A. one
• B. two
• C. five
• D. one fifth

Answer 1

The Correct Option is B

 The chemical reaction for the formation of KMnO₄ will look like–

2KMnO₄ + KI + H₂O → KIO₃ + 2MnO₂ + 2KOH

While determining the oxidation number from this reaction following values will be obtained-

Iodine's oxidation number increases from -1 in KI to +5 in KIO₃

But Magnesium’s oxidation number decreases from +7 in KMnO₄ to +4 in MnO₂

Oxidation number decrease in Mn will be 3 and for 2 such Mn atoms it’ll sum up to 6.

During the reduction reaction, the charge of 1 Iodine atom is balanced by 2 Mn atoms so, the correct answer will be 2 Moles of KMnO₄ is reduced during the reaction.

A few mentionable characteristics of KMnO₄ are–

• Potassium Permanganate crystallizes into dark purple crystals that are practically black and are structurally identical to those of KClO4. 6.4g of salt dissolved in 100g of water at 293 K, which is not very much.
• It exhibits strong temperature-dependent paramagnetism and bright color.
• While permanganate ion is diamagnetic, green manganate ions are paramagnetic.
• The overlap of the oxygen's p and manganese's d orbitals results in bonding.
• In acidic, basic, and neutral environments, KMnO4 is an effective oxidizing agent.
• KMNO4 has a molecular weight of 158.034 g/mol.
• Potassium permanganate has a density of 2.703 g/cc.
• The optimal storage temperature for potassium permanganate is ambient temperature.
• Potassium permanganate has a boiling point of 100 degrees Celsius.
• Potassium permanganate has a melting point of 240 degrees Celsius.