Question

In addition to a small amount of $KMnO_4$​ to conc.$H_2​SO_4$​, a green oily compound is obtained which is highly explosive in nature. Identify the compound from the following.
A. $Mn_2​O_7$​
B. $MnO_2​$
C. $MnSO_4​$
D. $Mn_2​O_3​$

Answer 1

Hint: The alkene double bond is a gateway functional group. Alkene reactions lead to many other functional groups that lay the foundation for the rest of your study of organic chemistry

Complete step by step solution:
 $ {\mathbf{M}}{{\mathbf{n}}_{\mathbf{2}}}{{\mathbf{O}}_{\mathbf{7}}} $ ​Arises as a dark green oil by the addition of concentrated $ {{\mathbf{H}}_{\mathbf{2}}}{\mathbf{S}}{{\mathbf{O}}_{\mathbf{4}}}\;{\mathbf{to}}\;{\mathbf{K}}{{\mathbf{M}}_{\mathbf{n}}}{{\mathbf{O}}_{\mathbf{4}}} $ ​. The reaction initially produces per manganic acid, $ {\mathbf{HMn}}{{\mathbf{O}}_{\mathbf{4}}} $ ​ (structurally, $ {\mathbf{HOMn}}{{\mathbf{O}}_{\mathbf{3}}} $ ​), which is dehydrated by cold sulfuric acid to form its anhydride, $ {\mathbf{M}}{{\mathbf{n}}_{\mathbf{2}}}{{\mathbf{O}}_{\mathbf{7}}}. $
 $ {\mathbf{2KMn}}{{\mathbf{O}}_{\mathbf{4}}} + {\mathbf{2}}{{\mathbf{H}}_{\mathbf{2}}}{\mathbf{S}}{{\mathbf{O}}_{\mathbf{4}}} \to {\mathbf{M}}{{\mathbf{n}}_{\mathbf{2}}}{{\mathbf{O}}_{\mathbf{7}}} + {{\mathbf{H}}_{\mathbf{2}}}{\mathbf{O}} + {\mathbf{2KHS}}{{\mathbf{O}}_{\mathbf{4}}} $
 $ {\mathbf{M}}{{\mathbf{n}}_{\mathbf{2}}}{{\mathbf{O}}_{\mathbf{7}}} $ Is highly explosive in nature.
In principle, many different reagents could add to a double bond to form more stable products; that is, the reactions are energetically favorable. Not all of these reactions have convenient rates, however. For example, the reaction of ethylene with hydrogen (to give ethane) is strongly exothermic, but the rate is very slow. A mixture of ethylene and hydrogen can remain for years without appreciable reaction. Adding a catalyst such as platinum, palladium, or nickel allows the reaction to take place at a rapid rate.

Note:
A wide variety of electrophilic additions involve similar mechanisms. First, a strong electrophile attracts the loosely held electrons from the pi bond of an alkene. The electrophile forms a sigma bond to one of the carbons of the (former) double bond, while the other carbon becomes a carbocation.