Question

Account for:

$\mathrm{MnO}$ is basic whereas ${\mathrm{Mn}}_2{\mathrm{O}}_7$is acidic in nature why?

Answer 1

• $\mathrm{MnO}$is basic and ${\mathrm{Mn}}_2{\mathrm{O}}_7$ is acidic because the oxide in the lower oxidation state of a metal is basic and oxide in the higher oxidation state of the metal is acidic.
• We can find out the oxidation state of manganese in $\mathrm{MnO}$ and ${\mathrm{Mn}}_2{\mathrm{O}}_7$.
• In $\mathrm{MnO}$, the oxidation state of oxygen is $-2$.Take the value for manganese as 'x'. Then $x+(-2)=0.x=+2$.The oxidation state of manganese is $+2$.
• In ${\mathrm{Mn}}_2{\mathrm{O}}_7$, the oxidation state of oxygen is $-2$.Take the value for manganese as 'x'. Then $2x+(-2\times 7)=0,x=+7$.
• Manganese is a transition element which is present at the d block of the periodic table.
• The transition element in the lower oxidation state will give the compound a basic character and the transition element in the higher oxidation state will give the compound an acidic character.

Thus, $\mathrm{MnO}$ is basic whereas ${\mathrm{Mn}}_2{\mathrm{O}}_7$ is acidic in nature.