Given below are two statements : Statement I : Potassium permanganate on heating at 573K forms potassium manganate. Statement II : Both potassium permanganate and potassium manganate are tetrahedral and paramagnetic in nature. In the light of the above statements, choose the most appropriate answer from the options given below :

Statement I is true but statement II is false

Statement I is false but statement II is true

Both statement I and statement II are false

Both statement I and statement II are true

D and F Block Elements PYQ — JEE Main 2021 · 17 Mar · Shift 1 · Q8 with Solution

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Correct answer: A

Check Statement I

Potassium permanganate on heating decomposes as:

$2KMnO_4 \xrightarrow{573\,K} K_2MnO_4 + MnO_2 + O_2$

Thus, on heating, potassium permanganate does form potassium manganate.

So, Statement I is true.

Check Statement II

We need to examine both shape and magnetic nature of:

$KMnO_4$ containing $MnO_4^-$
$K_2MnO_4$ containing $MnO_4^{2-}$

(a) Geometry

Both $MnO_4^-$ and $MnO_4^{2-}$ are oxyanions with four oxygen atoms around manganese and are tetrahedral.

So the geometry part is true for both.

(b) Paramagnetic/diamagnetic nature

For permanganate ion, $MnO_4^-$

Oxidation state of Mn:

$x + 4(-2) = -1 \Rightarrow x=+7$

Mn atom: $[Ar]3d^54s^2$

$Mn^{7+}$ becomes:

$[Ar]3d^0$

No unpaired electrons $\Rightarrow$ diamagnetic.

For manganate ion, $MnO_4^{2-}$

Oxidation state of Mn:

$x + 4(-2) = -2 \Rightarrow x=+6$

So $Mn^{6+}$ is:

$[Ar]3d^1$

One unpaired electron $\Rightarrow$ paramagnetic.

Hence, it is not true that both are paramagnetic.

So, Statement II is false.

Choose the correct option

Statement I: True
Statement II: False

Therefore, the correct option is:

$\boxed{A}$

Comparison with stored correct answer

Stored correct answer: A

My derived answer: A

They match.

D and F Block Elements question

D and F Block Elements question

(a) Geometry

(b) Paramagnetic/diamagnetic nature

For permanganate ion, $MnO_4^-$

For manganate ion, $MnO_4^{2-}$

More from D and F Block Elements

D and F Block Elements question

D and F Block Elements question

(a) Geometry

(b) Paramagnetic/diamagnetic nature

For permanganate ion, $MnO_4^-$

For manganate ion, $MnO_4^{2-}$

More from D and F Block Elements

(a) Geometry

(b) Paramagnetic/diamagnetic nature

For permanganate ion, MnO4−MnO_4^-MnO4−​

For manganate ion, MnO42−MnO_4^{2-}MnO42−​

More from D and F Block Elements

(a) Geometry

(b) Paramagnetic/diamagnetic nature

For permanganate ion, MnO4−MnO_4^-MnO4−​

For manganate ion, MnO42−MnO_4^{2-}MnO42−​

More from D and F Block Elements

For permanganate ion, $MnO_4^-$

For manganate ion, $MnO_4^{2-}$

For permanganate ion, $MnO_4^-$

For manganate ion, $MnO_4^{2-}$