Hydrocarbons and Halogenoalkanes
Home > Preview
The flashcards below were created by user
on FreezingBlue Flashcards.
What is a sigma bond?
A sigma bond is a covalent bond formed by the end-on overlap of two atomic orbitals lying along the axis of the bond
What is a pi bond?
A pi bond is a covalent bond formed by the sideways overlap of two parallel atomic orbitals lyingperpendicular to the axis of the bond
Which are stronger, pi bonds or sigma bonds?
Sigma bonds (as the end-on overlap is much moreefficient than side-on overlap)
What is hybridisation?
The process of mixing atomic orbitals in an atom to generate a set of new atomic orbitals called hybrid orbitals
What is sp3 bonding? And what type of hydrocarbons is it found in?
- sp3 bonding is when the three 2p orbitals and one 2s orbital mix to form degenerate hybrid orbitals
What is sp2 bonding? And what type of hydrocarbons is it found in?
- sp2 bonding is when the 2s orbital and two 2p orbitals mix to form hybrid orbitals
Alliances undergo substitution reactions with chlorine and bromine by a _______ _________ mechanism?
What are the three stages in a chain reaction?
What happens in the initiation step if methane is reacted with Cl?
Ultraviolet light provides energy for the reaction to start. Homolytic fission of Cl or Br occurs. This creates free radicals (atoms or groups or atoms with an unpaired electron) which are highly reactive.
What happens in the propagation step?
- Each chlorine radical that is produced goes on to attack a methane molecule removing a hydrogen atom from it to form HCl and a methyl radical: Cl. + CH4 ---> HCl + CH3.
- The methyl radical then attacks a chlorine molecule to form chloromethane and another chlorine radical: CH3. + Cl2 ---> CH3Cl + Cl.
- In each of the propagation steps one radicalsenders the reaction and another radical is generated . These steps sustain the reaction.
What happens in the termination step?
- Reactions in which radicals are used up and noT regenerated eg
- CH3. + Cl. ---> CH3Cl
- CH3. + CH3. ---> CH3CH3Cl. + Cl. ---> Cl2
How can alkenes be prepared in the lab?
- Dehydration of alcohols
- Base-induced elimination of hydrogen halides from monohalogenoalkanes
How are alcohols dehydrated in the lab?
By passing them over hot aluminium chloride or using concentrated sulphuric acid or orthophosphoric acid
Alkenes undergo addition reactions with hydrogen to form...?
Alkenes undergo addition reactions with halogens to form...?
Alkenes undergo addition reactions with hydrogen halides to form...?
Alkenes undergo addition reactions with water to form...?
The addition reaction of an alkene with hydrogen is also known as...? What is it catalysed by?
- Nickel or platinum
The addition reaction of an alkene with a halogen is also known as...?
The addition reaction of an alkene with hydrogen halide is also known as...?
The addition reaction of an alkene with water is also known as...? What is it catalysed by?
What is Markovnikov's rule?
Marokovinikov's rule states that when H-X or H-OH adds onto an unsymmetrical Allende the major product is the one in which the H atom ends up attached to the carbon atom of the double bond which already has the greater number of hydrogen atoms bonded to it
What type of intermediate is involved in the mechanisms in the of the following reactions:
- A cyclic ion intermediate
- A carbocation intermediate
- A carbocation intermediate
What is the difference between a primary, secondary and tertiary monohalogenoalkane?
- Primary - halogen atom on carbon attached to 1 other carbon atom
- Secondary - halogen atom on carbon attached to 2 carbon atoms
- Tertiary - halogen atom on carbon attached to 3 carbon atoms
What is the main reaction of monohalogenoalkanes?
Monohalogenoalkanes undergo elimination reactions to form...?
Monohalogenoalkanes react with alkalis to form...?
Monohalogenoalkanes react with alcoholic alkoxides to form...?
Monohalogenoalkanes react with ethanolic cyanides to form...?
Nitriles (which can be hydrolysed to carboxylic acids)
Monohalogenoalkanes react with ammonia to form...?
What would you like to do?
Home > Flashcards > Print Preview