Table of Contents
What reaction is catalysed by chlorine radicals?
Chlorine atoms catalyse the decomposition of ozone and contribute to the hole in the ozone layer.
What is the radical of Cl?
Chloride is the chlorine anion that forms the acid radical (negative portion) of some inorganic salts such as sodium chloride, potassium chloride, calcium chloride, etc. Chlorine gas exists in nature as a diatomic molecule. Chlorine in its gaseous state is a highly toxic gas that possesses a strong smell.
Is chlorine radical reactive?
The initiation step in alkane halogenation is homolysis of molecular chlorine (Cl2) into two chlorine radicals. Keep in mind that that virtually all radical species, chlorine radicals included, are highly reactive.
How chlorine free radicals are formed?
Because we want to stress the fact that the chlorine atoms have single unpaired electrons, then we call them chlorine free radicals – or more usually just chlorine radicals. Free radicals are formed if a bond splits evenly – each atom getting one of the two electrons. The name given to this is homolytic fission.
How chlorine radicals can Catalyse the destruction of ozone?
Chlorine is able to destroy so much of the ozone because it acts as a catalyst. Chlorine initiates the breakdown of ozone and combines with a freed oxygen to create two oxygen molecules. After each reaction, chlorine begins the destructive cycle again with another ozone molecule.
What are the products of the reaction between a chlorine radical and ozone?
The chlorine radical rapidly reacts with ozone (step 2) to form molecular oxygen and a chlorine monoxide radical.
Is chlorine atom a radical?
The free chlorine atom is a radical with one unpaired electron.
Why chlorine radical is more reactive than bromine radical?
This is because chlorination forms a strong H-Cl bond (103 kcal/mol) and bromination forms a much weaker H-Br bond (87 kcal/mol).
How do chlorine radicals break down ozone?
Is cl2 a free radical?
Initiation: Splitting or homolysis of a chlorine molecule to form two chlorine atoms, initiated by ultraviolet radiation . A chlorine atom has an unpaired electron and acts as a free radical.
How does chlorine affect ozone?
When chlorine and bromine atoms come into contact with ozone in the stratosphere, they destroy ozone molecules. One chlorine atom can destroy over 100,000 ozone molecules before it is removed from the stratosphere. Ozone can be destroyed more quickly than it is naturally created.
Which radicals cause ozone depletion?
The most prominent reactions are the HOx, NOx, and Cl radical chain reactions: These reactions are termed chain reactions because the ozone-destroying radical (e.g. HO) is regenerated by combination with an oxygen radical. One chlorine radical can destroy many ozone molecules in its lifetime.
How do chlorine and bromine react with ozone?
Reactive gases containing chlorine and bromine destroy stratospheric ozone in “catalytic” cycles made up of two or more separate reactions. As a result, a single chlorine or bromine atom can destroy many hundreds of ozone molecules before it reacts with another gas, breaking the cycle.
What is the difference between chlorine atom and chlorine radical?
The difference between chlorine radical and a chlorine molecule is that chlorine radical is formed when one chlorine atom does not find another chlorine atom to bind with. Chlorine atom has the capacity to exist in isolation.
Does chlorine react with hydrocarbons?
The process of halogenation of hydrocarbons occurs when chlorine reacts with saturated hydrocarbons in the presence of sunlight. The hydrogen atoms in the hydrocarbon are replaced by chlorine atoms in this process.
What elements does chlorine not react with?
Chlorine does not react directly with carbon and inert gases, oxygen and nitrogen. With other halogens, chlorine forms interhalogen compounds: for example, strong oxidizers — the fluorides ClF, ClF₃ and ClF₅.
How is chlorination different from bromination?
In chlorination, the reaction is exothermic, and the transition state resembles the reactants. According to Hammond’s postulate, we could say that this transition state is “early”. In bromination, the reaction is endothermic, and the transition state resembles the products.
What happens when two hydrogen radicals are added to chlorine?
The hydrogen radical can then react with a chlorine molecule to produce another chlorine radical: These two propagation steps set up a chain reaction, which terminates if two radicals combine: The probability of each of the four steps in the chain reaction is based on the relative concentrations of the species involved.
How many free radicals can be formed from one chlorine molecule?
This is more than the Cl–Cl bond strength (242 kJ mol -1) in the chlorine molecule, which consequently splits into two chlorine free radicals with one unpaired electron each:
Can hydrogen atom transfer reactions be catalyzed by photoredox?
Rohe, S., Morris, A. O., McCallum, T. & Barriault, L. Hydrogen atom transfer reactions via photoredox catalyzed chlorine atom generation. Angew. Chem. Int. Ed. 57, 15664–15669 (2018).
What free radical reactions are studied at Year 12?
Free radical reactions are studied at year 12, including free radical substitution reactions of halogens with alkanes, and the role of CFCs in the catalytic decomposition of ozone. Chlorine absorbs uv light, the energy of which is equivalent to ca 400 kJ mol -1.