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Question: \(C{H_3}C{H_2}Br\xrightarrow{{aqKOH}}A\xrightarrow{{KMn{O_4}/{H^ + }}}B\xrightarrow[\vartriangle ]{{...

CH3CH2Br→aqKOHA→KMnO4/H+B→△NH3C→alkaliBr2DC{H_3}C{H_2}Br\xrightarrow{{aqKOH}}A\xrightarrow{{KMn{O_4}/{H^ + }}}B\xrightarrow[\vartriangle ]{{N{H_3}}}C\xrightarrow[{alkali}]{{B{r_2}}}D . D is:
A) CH3BrC{H_3}Br
B) CH3CONH2C{H_3}CON{H_2}
C) CH2NH2C{H_2}N{H_2}
D) CH2Br2C{H_2}B{r_2}

Explanation

Solution

Reagents used in the conversion are very important. The aqKOH use, carry out nucleophilic substitution reaction while KMnO4/H+KMn{O_4}/{H^ + } is a very strong oxidizing agent. The ammonia (NH3)\left( {N{H_3}} \right) easily takes up protons in the reaction and BH2B{H_2} /alkali is a reagent used in Hoffmann bromamide reaction.

Complete step by step answer:
CH3CH2Br→aqKOHA→KMnO4/H+B→△NH3C→alkaliBr2DC{H_3}C{H_2}Br\xrightarrow{{aqKOH}}A\xrightarrow{{KMn{O_4}/{H^ + }}}B\xrightarrow[\vartriangle ]{{N{H_3}}}C\xrightarrow[{alkali}]{{B{r_2}}}D
First of all, let us break the sequential conversion, in order to make the conversion process easier for us.
Let us first look at this part of the reaction CH3CH2Br→aqKOHAC{H_3}C{H_2}Br\xrightarrow{{aqKOH}}A.
aqKOH acts a nucleophile here and the reaction is a bimolecular nucleophilic substitution reaction (SN2{S_N}2 reaction) as the ethyl bromide is a primary alkyl halide. Thus, we get
CH3CH2−Br→aqKOHCH3−CH−OHC{H_3}C{H_2} - Br\xrightarrow{{aqKOH}}C{H_3} - CH - OH
The ethanol formed in the reaction is then oxidized by acidified potassium permanganate to give the corresponding carboxylic acid.
That is,
CH3−CH2−OH→KMnO4/H+CH3−COOHC{H_3} - C{H_2} - OH\xrightarrow{{KMn{O_4}/{H^ + }}}C{H_3} - COOH
The NH3N{H_3} then takes up proton from the carboxylic forming ammonium ethanoate which when heated gives ethanamide.

The ethanamide then reacts with BH2B{H_2} /alkali to form methylamine.
CH3−CONH2→alkaliBH2CH3NH2C{H_3} - CON{H_2}\xrightarrow[{alkali}]{{B{H_2}}}C{H_3}N{H_2}
This is Hoffmann bromamide reaction. The amide formed contains one carbon atom less than amide.
Thus, the sequential conversion can be written as –

Option (C) is the correct option.

Note:
Students should understand that associated colloids, also called micelles, are generally electrolytes. They exist as ions at low concentration. It is above a particular concentration called critical micelle concentration (CMC) and above a temperature called Kraft temperature; these get associated and exhibit colloidal behavior. It is very important to note that the primary distinguishing features between a true solution and a colloidal solution is fundamentally the dimension of the constituent part.