Question

The incorrect statement is

• A. In manganate and permanganate ions. the $\pi$-bonding takes place by overlap of p-orbitals of oxygen and d-orbitals of manganese
• B. Manganate ion is green in colour and permanganate ion is purple in colour
  
• C. Manganate and permanganate ions are paramagnetic
• D. Manganate and permanganate ions are tetrahedral

Answer 1

The correct option is C Manganate and permanganate ions are paramagnetic

$\text{Manganate}\to Mn{O}_4^{2-}\to +6\text{(oxidation state)}\text{Permanganate}\to Mn{O}_4^{-}\to +7\text{(oxidation state)}$

Manganate contains 1 unpaired electron hence it is paramagnetic where as permanganetic contains no unpaired electrons hence it is diamagnetic.

Both have $d^{3}s$ hybridisation hence both have tetrahedral geometry.

Manganate ion is green in colour and permanganate ion is purple in colour.

Also, in manganate and permanganate ions, the $\pi$-bonding takes place by overlap of p-orbitals of oxygen and d-orbitals of manganese.

Hence, option (a) is the correct answer.