12 Alcohols and haloalkanes Flashcards
How can the rate of hydrolysis of haloalkanes be followed?
with the speed of the formation of a silver precipitate
What does CFC stand for?
chlorofluorocarbons
What is the definition of a nucleophile?
atom with a negative charge or an atom that has a δ− charge/ a species that can donate a lone pair of electrons
Is 2-chloropropane a primary, secondary, or tertiary haloalkane?
secondary
What colour precipitate will a bromoalkane form upon addition of silver nitrate?
Pale cream
What is the chemical formula for ozone?
O3
What type of reaction happens when a haloalkane reacts with aqueous sodium hydroxide or potassium hydroxide?
nucleophilic substitution
Why do haloalkanes contain polar bonds?
due to the difference in electronegativity between the halogens and carbon
Which Halogen–carbon bond is the most reactive?
C—I
Why do alcohols have a higher boiling point than comparable alkanes?
due to their stronger intermolecular bonds or hydrogen bonds
Are alcohols more volatile than alkanes?
alcohols are less volatile
How many OH group are there in a -triol molecule?
Three
Why are alcohols polar?
due to the difference in electronegativity between oxygen and hydrogen
What do primary alcohols partially oxidise to?
aldehydes
What do primary alcohols fully oxidise to?
carboxylic acids
What type of intermolecular bonding is found in alcohols but not in alkanes?
hydrogen bonding
What do secondary alcohols oxidise to?
Ketones
What do tertiary alcohols oxidise to?
they do not oxidise
What colour change can be seen in the oxidation of alcohols by potassium dichromate(VII)?
orange acidified potassium dichromate(VII) (Cr2O72−) will reduce to green chromium ions (Cr3+) in the reaction
How can you partially oxidise alcohols to aldehydes?
You get an aldehyde if you use an excess of the alcohol, and distil off the aldehyde as soon as it forms.
How do you fully oxidise alcohols to crboxylic acids?
The alcohol is heated under reflux with an excess of the oxidising agent. Make sure that the aldehyde formed as the half-way product stays in the mixture using a reflux condenser. When the reaction is complete, the carboxylic acid is distilled off.
What can secondary alcohols be oxidised to?
Secondary alcohols are oxidised to ketones - and that’s it.
How can you distinguish between the primary and secondary alcohols?
There are various things which aldehydes do which ketones don’t. These include the reactions with Tollens’ reagent, Fehling’s solution and Benedict’s solution.
A much simpler but fairly reliable test is to use cold Schiff’s reagent. In the presence of even small amounts of an aldehyde, it turns bright magenta.
How can gaseous alcohols be dehydrated to give an alkene.
If ethanol vapour is passed over heated aluminium oxide powder, the ethanol is essentially cracked to give ethene and water vapour.
