Understanding the Balanced Chemical Equation for Ethene and Bromine Water

Understanding the Balanced Chemical Equation for Ethene and Bromine Water

Bromine water and ethene react through a process known as an addition reaction, where bromine adds across the double bond in ethene. This reaction forms di-bromoethane. The balanced chemical equation for ethene with bromine water can be written as follows:

The Stepwise Reaction Mechanism

When ethene (C2H4) reacts with bromine water, ethene initially undergoes an electrophilic addition reaction. However, the carbocation formed can also react further with the bromide ion. Here's a detailed breakdown of the steps involved:

Step 1: Initial Electrophilic Addition

First, ethene reacts with bromine water to form a bromonium ion complex, which is a carbocation intermediate. This is represented by the following balanced equation:

[ text{C}_2text{H}_4 text{Br}_2 rightarrow text{CH}_2text{Br}-text{CH}_2text{Br}^{-} ]

Step 2: Reaction with Water Molecules

Due to the high concentration of water molecules in the reaction mixture, the carbocation can further react with water to form bromoethanol. The water molecules act as nucleophiles, leading to the following balanced equation:

[ text{CH}_2text{Br}-text{CH}_2text{Br}^{-} rightarrow text{CH}_2text{OH}-text{CH}_2text{Br} text{HBr} ]

Further Product Formation

The reaction can proceed to form di-bromoethane (1,2-dibromoethane), which is the major product of the reaction. This further addition of bromine across the double bond can be represented as follows:

[ text{CH}_2text{CH}_2 text{Br}_2 rightarrow text{CH}_2text{Br}-text{CH}_2text{Br} ]

Summary of the Reaction Mechanism

The combined mechanism of the reaction can be summarized as:

[ text{C}_2text{H}_4 text{Br}_2 xrightarrow{Delta} text{CH}_2text{Br}-text{CH}_2text{Br} rightarrow text{CH}_2text{OH}-text{CH}_2text{Br} text{HBr} ]

Conclusion

The balanced chemical equation for the reaction of ethene with bromine water results in the formation of di-bromoethane and bromoethanol. This reaction is an excellent example of an electrophilic addition process, involving the formation of a carbocation intermediate.

Keywords

Chemical Equation, Bromine Water, Ethene Addition Reaction