Choose the incorrect statement from the following:

The correct answer is Option (3) → permanganate ion is paramagnetic in nature

A species is paramagnetic only if it has unpaired electrons. In the permanganate ion, \( \ce{MnO4-} \), the oxidation state of manganese is found from the charge:

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

Mn (Z = 25) is \( \mathrm{[Ar]\,3d^{5}\,4s^{2}} \). Losing all seven of these electrons gives \( \ce{Mn^7+} \): \( \mathrm{3d^{0}} \). With no d electrons there is nothing unpaired, so the permanganate ion is diamagnetic. (The manganate ion, \( \ce{MnO4^2-} \), with Mn(VI) and one 3d electron, is the paramagnetic one.)

• Option (1) permanganate ion is tetrahedral — True for the permanganate ion. Four oxygen atoms surround the manganese atom at the corners of a tetrahedron.

• Option (2) pi-bonding in permanganate ion takes place by overlap of p orbital of oxygen with d orbital of manganese — True for the permanganate ion. Besides the Mn–O σ bonds, the filled p orbitals of oxygen overlap with the empty d orbitals of manganese to form the π bonds.

• Option (3) permanganate ion is paramagnetic in nature — Not true for the permanganate ion (it is diamagnetic). Mn(VII) is 3d⁰, with no unpaired electron.

• Option (4) permanganate ion is purple in colour — True for the permanganate ion. \( \ce{KMnO4} \) gives an intense purple solution. With a \( d^0 \) ion the colour cannot come from a d–d transition; it is due to charge transfer of electrons from oxygen to manganese.

NCERT (2026-27 edition):
Oxides and Oxoanions of Metals – …