Reactions Of Hydrocarbons Flashcards
What are the two possible reactions involving alkanes?
Combustion and substitution with chlorine and bromine.
What are the products of an Alkane combustion reaction?
Carbon dioxide and water ( C and CO if incomplete )
What do alkane substitution reactions form?
Alkyl halides and other products.
Describe an alkane substitution reaction.
Hydrogen atoms are replaced one at a time by Cl- or Br- . They require heat or UV light.
What would the evidence of an alkane substitution reaction?
Colour disappears and pH becomes lower
What are the four possible reactions involving alkenes and alkynes?
halogenation (Br2 or Cl2), hydrogenation (H2), hydrohalogenation (HBr), hydration (H2O).
What are the catalysts used in an alkene/alkyne hydrogenation reaction?
Ni/Pt
Which reaction uses a catalyst?
alkene/alkyne hydrogenation reaction
What is the product of an alkene/alkyne halogenation reaction?
An alkane containing 2 halogens
What is the product of an alkene/alkyne hydrogenation reaction?
alkane
What is the product of an alkene/alkyne hydrohalogenation reaction?
An alkane containing 1 halogen
What is the product of an alkene/alkyne hydration reaction?
alcohol
Describe what an addition reaction is.
Atoms are added to double or triple bond. One bond in multiple bond breaks. 2 reactants form 1 product with no lost hydrogens.
How does an alkyne become an alkane?
It undergoes a reaction with an excess of the reactant (ex: in halogenation a 1:2 mol ratio of Br2)
Explain Markovnikov’s rule.
When 2 non-identical toms are being added, (like HCl or H2O), to an unsymmetrical alkene, (like propene), there are two possible ways it could add. However, only one major product is formed.
How can you tell what the major product will be?
The hydrogen will attach to the carbon with the most hydrogens to form the major product.
What is significant about the major and minor products?
They are isomers.
Give a simple instruction for dealing with Markovnikov’s rule.
When a compound HX is added to an unsymmetrical alkene (across the double bond), attach the hydrogen to the carbon with the most hydrogens!