What is the product after treating ethene successively with chlorine and water, sulfuric acid, and potassium hydroxide?

**Question:** 



> 
> Ethene reacts with $\ce{Cl2}$ in $\ce{H2O}$ to form A. A on reaction with $\ce{H2SO4}$ followed by heating gives B. B on reaction with alcoholic $\ce{KOH}$ gives C. Find C.
> 
> 
> 


**My answer is:** 


A: $\ce{CH2(OH)CH2Cl}$  

B: $\ce{CH2=CHCl}$  

C: ethyne. 


**Explanation:**


Ethene on reaction with chlorine water undergoes addition reaction to give A. A on reaction with $\ce{H2SO4}$ followed by heating undergoes dehydration to give B. B on reaction with alcoholic $\ce{KOH}$, undergoes elimination to give ethyne.


But the answer given is $\ce{CH2=CH-O-CH=CH2}$.


Where I am going wrong and what are the products?




The first reaction is a [hydrochlorination](https://en.wikipedia.org/wiki/Hydrohalogenation) reaction:


[![step 1](https://i.stack.imgur.com/RiVTY.png)](https://i.stack.imgur.com/RiVTY.png)


The second reaction is an [acid catalyzed ether synthesis](https://en.wikipedia.org/wiki/Ether#Dehydration_of_alcohols). The the solution is full of other 2-chloroethanol, which is capable of acting as a nucleophile in an $\mathrm{S\_N2}$ reaction to eject $\ce{H2O}$. This is reaction will have a much lower energy barrier than the dehydration you proposed, which requires the extraction of an aliphatic hydrogen. The ether synthesis mechanism can be seen here:


[![step 2](https://i.stack.imgur.com/GuP4e.png)](https://i.stack.imgur.com/GuP4e.png)


The final step is a series of two [$\mathrm{E2}$ reactions](https://en.wikipedia.org/wiki/Elimination_reaction#E2_mechanism) (shown condensed here):


$\hspace{4cm}$[![enter image description here](https://i.stack.imgur.com/t2BvB.png)](https://i.stack.imgur.com/t2BvB.png)


 5