Draw the reaction mechanism for the formation of ethanol from bromoethane and water and name the mechanism.

The first step is the draw out the molecules in question to understand what is happening in the reaction. You can see that the bromine atom has been substituted for an alcohol group (OH) in the enthane molecule. Water has a lone pair of electrons on oxygen and so can act as an electron donor (nucleophile) to the carbon bonded to the bromine to help the substitution reaction along.

From this knowledge, you can use your curly arrows to draw the lone pair on Oxygen of the water to attack the carbon atom bonded to bromine. But, carbon can only have 4 bonds and so you need to break one bond. We are hoping to lose the bromine atom and so you should break the C-Br bond with a curly arrow pointing to Br. You now have a the molecule CH3CH2O+H2. You need to take a hydrogen from the Oxygen to stop making it positive charge and so that the O only has 2 bonds. Another water molecule can act like a nucleophile and a curly arrow is drawn from the water O to one of the H's attached to the ethanol molecule. Another curly arrow is drawn to break the O-H ending the arrow at O to give it's lone pair of electrons back. You now have CH3CH2OH, the desired molecule. The by-products are Br- and H3O+

As to name the mechanism, you know there are nucleophiles involved and it is a substition and so the mechanism is called: nucleophilic substitution.

HH
Answered by Henry H. Chemistry tutor

7198 Views

See similar Chemistry A Level tutors

Related Chemistry A Level answers

All answers ▸

What is solvent leveling? How can we distinguish between two strongly acidic solutions? (This is a challenging question and is included for interest only)


Given the following equilibrium: H2O + H2O <-> H3O+ + OH- and the Kw = 10^-14, determine the concentration of OH- species after the addition of 1 mmol of HCl to 1 L of neutral water.


Explain why the product of nucleophilic addition of a cyanide ion to the ketone CH3COCH2CH3 shows no optical activity


Why is there a difference in mechanism between tertiary halogenoalkanes and primary halogenoalkanes in nucleophilic substitution?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences