Alcohols - Exam Questions Flashcards
State why tertiary alcohols are not easily oxidised.
no hydrogen atom on the central carbon
State the test and result for an aldehyde.
Fehling’s solution - turns brick red
negative result = blue
State the advantages of making ethanol by the hydration of ethene.
- fast reaction
- pure product
- continuous cycle
State the disadvantages of making ethanol by the hydration of ethene.
- high technology
- expensive equipment
- ethene is from non-renewable resources
Outline a mechanism for the dehydration of alcohol to form an alkene in the presence of an acid catalyst.
H+ bonds with OH
OH2 breaks off - carbocation
CH breaks to form double bond - H+ ion + alkene
Give a suitable dehydrating agent for a dehydration reaction.
concentrated H2SO4
Name the types of reaction illustrated by:
glucose –> ethanol
ethanol –> ethene
- fermentation
- dehydration
State what must be added to an aqueous solution of glucose so that ethanol is formed.
yeast
Give one advantage of using ethanol as a fuel compared with using a petroleum fraction.
ethanol is renewable
Which reagent is required for the reaction of a haloalkane to form an alkene.
alcoholic hydroxide
State the purpose of the anti-bumping granules.
to prevent vigorous boiling
Name the mechanism for the dehydration reaction of an alcohol to form alkenes.
elimination
Identify a catalyst for the dehydration of ethanol to form ethene.
Concentrated H2SO4
Identify a catalyst and a reagent for converting a vegetable oil into margarine.
nickel + hydrogen
State what is meant by the term hydration.
addition of water
Give a suitable reagent & reaction conditions for the oxidation of an alcohol to form the carboxylic acid as the major product.
- potassium dichromate in excess
- concentrated sulfuric acid
- heat under reflux
State three essential conditions necessary to produce a good yield of ethanol from fermentation.
- yeast
- anaerobic
- temperature of 30 degrees celsius
Name & outline the mechanism for the reaction of a haloalkane to produce an alkene.
Elimination: (ethanolic OH)
- OH attacks C-H adjacent to C-X
- double bond forms
- X breaks of, H20 + X-
Conditions for the hydration of ethene into ethanol.
high temperature + high pressure
SiO2 coated in phosphoric acid (catalyst)
