Question

Incorrect statement about $M{n}_2{O}_7$ is :

• A. It is purple in colour
• B. $Mn$ is tetrahedrally surrounded by $O$ atom
• C. $Mn–O–Mn$ linkage is present
• D. It is a covalent oxide

Answer 1

The correct option is A It is purple in colour

Structure of $M{n}_2{O}_7$ in which $Mn$ is terahedrally surrounded by $O$-atom.


In $M{n}_2{O}_7,Mn$ has the highest oxidation state and leads to covalent bonding. The reason for this is manganese and oxygen electronegativity difference is more. But the electronegativity of $Mn$ increase with oxidation state and reaches the value closer to oxygen when it is $+7$ oxidation state.
$\Rightarrow M{n}_2{O}_7$ is green in color but when dissolve in water gives permagnetic acid which is purple in color $\left(HMn{O}_4\right)$ .