The D And F Block Elements Ques 42

42. $KMnO_4$ can be prepared from $K_2 MnO_4$ as per the reaction:

$3 MnO_4^{2-}+2 H_2 O \rightarrow$

$ 2 MnO_4^{-}+MnO_2+4 OH^{-} $

The reaction can go to completion by removing $OH^{-}$ions by adding.

[NEET 2013]

(a) $KOH$

(b) $CO_2$

(c) $SO_2$

(d) $HCl$

Show Answer

Solution:

  1. (b) $HCl$ and $SO_2$ are reducing agents and can reduce $MnO_4^{-}$. $CO_2$ which is neither oxidising and nor reducing will provide only acidic medium. It can shift reaction in forward direction and reaction can go to completion.