Question

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

• A. $ Sb{{F}_{5}} $
• B. $ Mn{{F}_{3}} $
• C. $ KSb{{F}_{6}} $
• D. $ Mn{{F}_{4}} $

Answer 1

Answer: (A)

Stronger Lewis acid, $ Sb{{F}_{5}} $ displaces the weaker one $ (Mn{{F}_{4}}) $ from its salt. $ Mn{{F}_{4}} $ is unstable and readily decompose to give $ Mn{{F}_{3}} $ and fluorine. $ {{K}_{2}}Mn{{F}_{6}}+2Sb{{F}_{5}}\xrightarrow[{}]{{}}2Ksb{{F}_{5}}+\underset{unstable}{\mathop{Mn{{F}_{4}}}}\, $
$ 2Mn{{F}_{4}}\xrightarrow[{}]{{}}2Mn{{F}_{3}}+{{F}_{2}} $