The first step occurs when a chlorine atom approaches methane and picks off a hydrogen atom, leaving a methyl radical. This is endothermic by 2 kcal/mol.
Is chlorination endothermic or exothermic?
In chlorination, the reaction is exothermic, and the transition state resembles the reactants.
Is the reaction between methane and chlorine endothermic?
If more energy is put into a reaction than is given off, the ΔH is positive, the reaction is endothermic and not energetically favorable. … Since, the ΔH for the chlorination of methane is negative, the reaction is exothermic.
What type of reaction is chlorination of methane?
One of the hydrogen atoms in the methane has been replaced by a chlorine atom, so this is a substitution reaction.
Why does methane not react with chlorine in dark?
Hint: Methane reacts with Chlorine in the presence of light . … Since the reaction proceeds through a free radical intermediate, it requires some kind of energy for forming the free radicals. When in dark, there is no such energy for the free radicals formation to take place.
Why chlorination is faster than bromination?
Chlorination is faster than bromination because chlorine is more reactive.
Is free radical chlorination exothermic?
A way to answer these questions is to look at the change in enthalpy (ΔH) that occurs when the reaction takes place. … Since, the ΔH for the chlorination of methane is negative, the reaction is exothermic. Energetically this reaction is favorable.
Why is reaction between methane and chlorine?
One of the hydrogen atoms in the methane has been replaced by a chlorine atom, so this is a substitution reaction. However, the reaction doesn’t stop there, and all the hydrogens in the methane can in turn be replaced by chlorine atoms.
Why do alkanes not react with iodine?
The data above indicate that the halogen radicals have different reactivity, fluorine is most reactive and iodine is least reactive. The iodine radical is very unreactive with overall “+” enthalpy, so iodine does not react with alkane at all.
What is chlorination of methane?
One of the hydrogen atoms in the methane has been replaced by a chlorine atom, so this is a substitution reaction. … The mechanism involves a chain reaction. During a chain reaction, for every reactive species you start off with, a new one is generated at the end – and this keeps the process going.