Chemistry Transition Elements DUHS 2023
PMDC Verified Question 21 of 68
What is the oxidation number of Mn is \( KMnO_{4} \)?
A
+2
B
+4
C
+6
D
+7
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: +7
Concept:

The algebraic sum of the oxidation states of all atoms in a neutral compound is exactly zero.

Formula:

$$ \sum \text{Oxidation States} = 0 $$

Solution:

  • In Potassium Permanganate (\(KMnO_4\)), the known oxidation states are Potassium (\(K = +1\)) and Oxygen (\(O = -2\)).


  • Let the oxidation state of Manganese (\(Mn\)) be \(x\).


  • Set up the equation:
    \( 1(K) + 1(Mn) + 4(O) = 0 \)


  • \( (+1) + x + 4(-2) = 0 \)


  • \( 1 + x - 8 = 0 \)


  • \( x - 7 = 0 \implies x = +7 \)


Why other options are incorrect:

  • The other options correspond to Manganese in different compounds, such as \(MnSO_4\) (+2), \(MnO_2\) (+4), and \(K_2MnO_4\) (+6).

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