Question

Which of the following is not true about $M{n}_2{O}_7$?

• A. It is acidic in nature
• B. It is a very good oxidizing agent
• C. It is a stable anhydride of permanganic acid and is stable at temperatures above $60{}^{\circ }C$
• D. $Mn$ has a tetrahedral geometry in $M{n}_2{O}_7$

Answer 1

The correct option is C It is a stable anhydride of permanganic acid and is stable at temperatures above $60{}^{\circ }C$

a) In $M{n}_2{O}_7$, $Mn$ is in its +7 oxidation state. So, it has a tendency to accept electrons and hence, is acidic in nature.
b) Since $Mn$ is in its highest oxidation state, it is a very good oxidising agent.
c) Permanganic acid is $HMn{O}_4$. Thus, $M{n}_2{O}_7$ is an anhydride of permanganic acid, but it decomposes near room temperature and it decomposes explosively above $55{}^{\circ }C$.
d) $Mn$ has a tetrahedral geometry in $M{n}_2{O}_7$.