Question

$F _{2}$ formed by reacting $K _{2} MnF _{6}$ with

• A. $SbF _{ s }$
• B. $MnF _{3}$
• C. $KSbF _{6}$
• D. $MnF _{4}$

Answer 1

Answer: (A)

$K _{2} MnF _{6}$ with $SbF _{5}$ forms $F _{2}$. In this reaction stronger I.ewis acid $ShF _{5}$ displaces the weaker one $\left( MnF _{4}\right)$ from its salt. $MnF _{4}$ is unstable and readily decompose to give $MnF _{3}$ and fluorine
$K _{2} MnF _{6}+2 SbF _{5} \longrightarrow 2 KSbF _{6}+\underset{\text { (unstable) }}{ MnF _{4}}$
$MnF _{4} \longrightarrow M n F _{3}+\frac{1}{2} F _{2}$