Learn about Organic Chemistry 14, in this comprehensive video by bannanaiscool.
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The second type of important organic reaction is an addition reaction. Now, the substitution reactions occur with single bond in the benzene rings and here models can illustrate the collision principle really well. Take a look at these carbons in here. They're kind of buried, aren’t they by their hydrogen which surround them. So in all likelihood, theoretically with collision theory what’s going to happen is their chlorine comes along, it doesn’t necessarily have the percentage probability of colliding with the carbon and disturbing that, so much as it does with the hydrogen. And when it does, it can substitute and reaction can take place. That’s why substitution is the most likely reaction to occur with single bonded types of molecules and benzenes too. But then when you have a double bond, there is likelihood that instead of hitting and substituting with an outer hydrogen which still can happen, you're going to get a collision with the carbons here that are bonded. That then will open up perhaps a double bond to a single and allow two substitutions to take place, or just to add both of your diatomic species on, or whatever you have that you could add on two of and you're going to be able to then have an addition reaction. So when you break an addition-reaction or you're going to flash it out on paper, here is propane reacting with fluorine. What’s going to happen? You're going to pop open the double bond and you're going to put both of the fluorine so you're going to end up with a three carbon chain and just be careful the double bond is here, so it’s between these two here that you're going to have fluorine. Now how do you name that? That’s going to be, well that’s a propane with a fluorine of two. So it’s going to be one, two—difluoropropane. When you look at this one, there’s a triple bond now what do I do? Well if you can have a really successful collision with that, you can actually take that triple bond and bust it down into a single. Go into a double first and then you can probably get into a single. It’s a stepwise reaction. But in the end one, two and then three, four to put on. Four? We only have two chlorines here. And so what we do is we bust that down into a single and there’s your propane that came from this which was propene and then we’ve put chlorine two here and two here and what do we get? We get one, one, two, two tetrachloropropane, addition reactions!