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# Mechanisms help!!! watch

1. "Butane, C4H10, reacts with Cl2 to form a mixture of chlorinated products

One possible product is C4H9Cl

C4H10 + Cl2 --> C4H9Cl + HCl

(i) State the conditions: UV light and excess Cl2 to lower further substitution

(ii) Write equations to show the mechanism of this reaction. Stuck on this!!

(iii) Write one equation for a reaction that would terminate this mechanism.

(iv) State the type of bond fission involved in the initiation step: Heterolytic fission.

Please help!!!

Thanks
2. (Original post by matt_copas)
"Butane, C4H10, reacts with Cl2 to form a mixture of chlorinated products

One possible product is C4H9Cl

C4H10 + Cl2 --> C4H9Cl + HCl

(i) State the conditions: UV light and excess Cl2 to lower further substitution

(ii) Write equations to show the mechanism of this reaction. Stuck on this!!

(iii) Write one equation for a reaction that would terminate this mechanism.

(iv) State the type of bond fission involved in the initiation step: Heterolytic fission.

Please help!!!

Thanks
Hey read up on free radical chlorination. This might help.

http://www.chemguide.co.uk/mechanism...ch4andcl2.html
3. (Original post by shengoc)
Hey read up on free radical chlorination. This might help.

http://www.chemguide.co.uk/mechanism...ch4andcl2.html
ATM ive got:

(iii) Cl2 ---> 2[Cl] ([] is radical coz thats what im using to represent it :P)

C4H10 + 2[Cl] --> C4H9Cl + HCl

Am i missing something?
4. (Original post by matt_copas)
ATM ive got:

(iii) Cl2 ---> 2[Cl] ([] is radical coz thats what im using to represent it :P)

C4H10 + 2[Cl] --> C4H9Cl + HCl

Am i missing something?
Very commonly, people often write

C4H10 + [Cl] --> [C4H9] + HCl PROPAGATION
[C4H9] + Cl2 ---> C4H9CL + [Cl] PROPAGATION

Then, for termination, you could write
2[C4H9] ----> C8H18
etc
5. (Original post by shengoc)
Very commonly, people often write

C4H10 + [Cl] --> [C4H9] + HCl PROPAGATION
[C4H9] + HCl ---> C4H9CL + [Cl] PROPAGATION

Then, for termination, you could write
2[C4H9] ----> C8H18
etc
I think you meant:

[C4H9] + Cl2 ---> C4H9Cl + [Cl] PROPAGATION
6. (Original post by charco)
I think you meant:

[C4H9] + Cl2 ---> C4H9Cl + [Cl] PROPAGATION
yup, weaker Cl-Cl bond over H-Cl bond
7. (Original post by shengoc)
yup, weaker Cl-Cl bond over H-Cl bond
well that and the fact that a hydrogen atom disappeared and an extra chlorine appeared in the products!
8. part (iv) is Homolytic not heterolytic. the Cl-Cl bond breaks so that each Cl atom gains an electron

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