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!
What is the possible reaction for an alkyl halide?
elimination
What are the prodcuts of an elimination reaction of an alkyl halide?
alkene (and technically Na+, Br-, OCH2CH3-, H+)
describe how alkyl halides form alkenes.
by eliminating a hydrogen and its adjacent halide ion, forming a double bond.
What type of reactions do bulky bases undergo?
Elimination
What is an example of a bulky base?
Sodium ethoxide
What are the possible reactions involving alcohols?
addition, elimination, condensation
What are the reactants and products of an alcohol addition/ preparation?
Alkene + water = alcohol
In other words, what is the alcohol addition reaction?
A hydration of alkene
WHat are the reactants and products of an alcohol elimination reaction?
Alcohol + bulky base = alkene (2 possibilities of shape)
Describe an alcohol elimination reaction.
The reverse of an addition reaction. A hydrogen and OH group are removed from a neighbouring Carbon. They form H2O and a double bond.
How do you prepare an ether?
Alcohol + Alcohol (Condensation of alcohols)
how do you prepare an ester?
Carboxylic acid + Alcohol (Condensation)
What do the products of condensation reactions always include?
H2O
How do you prepare an aldehyde?
Oxidizing a primary alcohol
How do you prepare a ketone?
Oxidizing a secondary alcohol
What are the two ways to prepare an alcohol?******
Addition reactions: adding water to an alkene.
OR adding hydrogen to an aldehyde/ketone
How do you prepare a carboxylic acid?
Oxidizing an aldehyde
What is an alkyl halide?
compounds in which one or more hydrogen atoms in an alkane have been replaced by halogen atoms
What is the only type of reaction that Markovnikov’s rule applies to?
addition reactions
What is the difference between hydrolysis and hydration?
Hydration is an addition reaction (creates only one product).
Hydrolysis splits a compound into 2 using water.
What are the products of the hydrolysis of an ester?
carboxylic acid and alcohol.
Why are there two possibilities of products for the elimination of an alcohol?
Because (if the OH is in the middle) there are 2 carbons with hydrogens adjacent to the C with OH group, so either one can form a double bond.
What is an elimination reaction?
When two substituents are removed from a molecule in either a one or two-step mechanism.
What are 4 examples of addition reactions?
halogenation, hydrogenation, hydrohalogenation, hydration
What are the products of the hydrogenation of an aldehyde/ketone?
Primary/secondary alcohol.
What is an example of an elimination reaction?
Dehydration/condensation
What is a substitution reaction?
Reaction in which a hydrogen atom or functional group is replaced by a different atom or functional group.
What are two features you can use to recognize a substitution reaction?
1.
