Question

In methyl alcohol solution, bromine react with ethylene to yield \[BrC{H_2}C{H_2}OC{H_3}\]​ in addition to \[1,2 - \]dibromoethane because:
A. Methyl alcohol solvate \[B{r^ - }\]
B. The intermediate ion formed initially may react with \[B{r^ - }\]or \[C{H_3}OH\]
C. This is free radical reaction
D. The reaction follows Markovnikov’s rule

Answer 1

Hint:Methanol, the simplest alcohol and an organic molecule having the formula \[C{H_3}OH\], is also referred to as methyl alcohol among other names. It has a pronounced alcoholic odour resembling that of ethanol and is a colourless, light, volatile liquid that is combustible. The C-OH bond is partially polar due to the difference in electronegativity.

Complete step-by-step answer:The addition of bromine to alkene is a type of electrophilic addition reaction. Bromine will break into $Br^-$ and $Br^+$ ion. The $Br^+$ ion first attacked on alkene to form carbocation $C^+{H_2} - C{H_2}Br$. This carbocation will form a cyclic intermediate which is known as bromonium ion. The intermediate bromonium ion initially generated may react with \[B{r^ - }\]or \[C{H_3}OH\]. This is due to the fact that \[C{H_3}OH\] can break into \[C{H_3}O^-\] and $H^+$ ions. The \[C{H_3}O^-\] attacks on bromonium ion to form additional product.

\[C{H_2} = C{H_2} + B{r_2}\xrightarrow{{C{H_3}OH}}BrC{H_2}C{H_2}OC{H_3}\]

Therefore, bromine combined with ethylene to produce \[BrC{H_2}C{H_2}OC{H_3}\] in addition to \[1,2 - \]dibromoethane in a methyl alcohol solution.

Option ‘B ’ is correct

Note: The reaction of bromine water with unsaturated organic is a important reaction in qualitative analysis as this reaction helps in the detection of double or triple bonds. The bromine water loses its colour after the reaction with unsaturated organic compounds such as alkenes.