Help! My Chem. text shows ethylene with it's 2 double bonds between the 2 carbon atoms, and 4 normally bonded hydrogen atoms, and says "ethylene readily combines with 2 atoms of chlorine, forming ethylene dichloride".

 

What's troubling me is that the diagram showing ethylene dichloride has only ONE double bond joining the carbons.

 

Now, is that not di-chloroethane? How does one know, or differentiate between ethylene dichloride which was derived from ethylene, and dichloroethane, which was not?

 

In other words, are ethylene dichloride and dichloroethane the exact SAME COMPOUND?

 

imp

ethylene has a single double bond. i don't know where you got the idea there was 2.

 

ethylene dichloride(systematic name: dichloroethene) has a double bond. dichloroethane does not. they are different compounds.

[ce]

H2C=CH2 + Cl2 --> Cl-CH2-CH2-Cl

[/ce]

 

In words: Ethylene plus chloride gives 1,2-dichloroethane.

 

Ethylene has 1 double bond. 1,2-Dichloroethane has no double bonds at all.

 

An example of a compound with 2 double bonds is for example CO2. It looks like [ce]O=C=O[/ce]. Notice the two "=" signs that are both a double bond.

Suffixes,

ane: single C-C bond

ene: double C=C bond

yne: tripple C=C bond

 

(the prefix just tell you how Many Carbons.)

the reason ethylene dichloride has the same beginning to its name as ethylene is probably that the reaction was first performed before people fully understood the reaction. Perhaps they thought it was ionic, since the name seems to suggest that.

Away from Chem. a long time- I was calling a single pair of electrons joining 2 carbons together a "double bond", and thusly ethylene has 2 "double bonds", which I meant to mean 2 PAIRS of electrons.

 

So, having clarified my poor terminology, the question remains unanswered:

 

a molecule of ethylene will combine with 2 chlorine atoms, forming ethylene dichloride, but the structure then contains only a SINGLE bond (2 electrons) between the 2 carbons, thusly making it IDENTICAL to dichloroethane in structure, no?

 

Or am I still missing the boat? imp

The product of the reaction of ethylene and chlorine is dichloroethane.

Dichloroethane is also known as ethylene dichloride even though (unlike ethylene) it no longer has a double bond.

It's a quirk of old nomenclature. Look on the bright side, we no longer refer to the stuff as "oil of dutch chemists".

The product of the reaction of ethylene and chlorine is dichloroethane.

Dichloroethane is also known as ethylene dichloride even though (unlike ethylene) it no longer has a double bond.

It's a quirk of old nomenclature. Look on the bright side, we no longer refer to the stuff as "oil of dutch chemists".

 

I'm grateful for this clarification, as it answers, finally, a nagging question which has prevailed in my mind since College Chemistry (in 1971!)

 

My text says ethylene can ADD chlorine atoms, and is therefore called an UNsaturated compound. Ethane reacts with chlorine by SUBSTITUTION ONLY, and is therefore called a SATurated compound.

 

Since the diagrams shown for ethylene dichloride and dichloroethane are identical, I have often wondered whether one diagram was mis-printed.

 

Finally, clarity is established!! imp