JEE Main On 16 April 2018 Question 7
Question: When $ XO _2 $ is fused with an alkali metal hydroxide in presence of an oxidizing agent such as $ KNO _3; $ a dark green product is formed which disproportionaltes= in acidic solution to afford a dark purple solution X is: [JEE Main 16-4-2018]
Options:
A) Cr
B) V
C) Ti
D) Mn
Show Answer
Answer:
Correct Answer: D
Solution:
$ \underset{(green)}{\mathop{MnO _2+2KOH+KNO _3\to K _2MnO _4+KNO _2+H _2O}}, $
Disproportionation reaction is as following:
$ \underset{(purple)}{\mathop{MnO_4^{-}2+4{H^{+}}\to 2MnO_4^{-}+MnO _2+2H _2O}}, $
