Flashcards in Alcohols and Haloalkanes Deck (124)
What is the general formula of an alcohol?
Cn H2n+1 OH
What is the suffix of an alcohol with 2 hydroxyl (OH) groups?
What is a primary alcohol?
An alcohol where the -OH group is attached to a carbon with 1 alkyl group attached
What is a secondary alcohol?
An alcohol where the -OH group is attached to a carbon with 2 alkyl groups attached
What is a tertiary alcohol?
An alcohol where the -OH group is attached to a carbon with 3 alkyl groups attached
What is an alkyl group?
An alkane with a Hydrogen removed e.g CH3
What is electronegativity?
The ability of an atom to attract the bonding electrons in a covalent bond
Why are alcohols classed as polar molecules?
Because the electronegative hydroxyl groups pulls the electrons in the C-OH bond away from the carbon atom, forming a dipole
What dipoles are there in an O-H bond?
ẟ- O-H ẟ+
In an alcohol, what does the partial positive charge on the Hydrogen atom in the hydroxyl group cause?
It attracts the lone pairs on an oxygen from a neighbouring molecule, forming a Hydrogen bond
What happens, in terms of bonds, when you mix an alcohol with water?
Hydrogen bonds form between the -OH group and the H2O
What is the trend in solubility of alcohols as they increase in size?
As alcohols increase in size, they become less soluble in water
Why do alcohols become less soluble in water as they increase in size?
Smaller alcohols are more polar, meaning the Hydrogen bonding lets it mix freely with water. In larger alcohols, most of the molecule is a non-polar carbon chain, so there's less attraction for the polar H2O molecules
Describe the volatility of alcohols
They have a low volatility
Why do alcohols have a low volatility?
Because they can form Hydrogen bonds (strongest type of intermolecular force) meaning it takes more energy to evaporate to a gas
What can be said about the boiling point of alcohols?
They have a relatively high boiling point
Why do alcohols have a relatively high boiling point?
Because they can form Hydrogen bonds (strongest type of intermolecular force) meaning it takes more energy to break the intermolecular bonds
What is the name of the reaction when an alcohol reacts with compounds containing Halide ions?
What does an alcohol turn into when undergoing a substitution reaction?
A Haloalkane, as the -OH group is replaced by the halide
What catalyst is used in an alcohol substitution reaction?
An acid catalyst, such as H2SO4 (sulfuric acid)
How do you make an alkene from an alcohol?
You can do an elimination reaction, which eliminates the water from the alcohol
What is a substitution reaction?
A reaction where some atoms from one reactant are swapped with atoms from another reactant
What is an elimination reaction?
A reaction in which a pair of atoms or group of atoms are removed from an organic compound
What 2 possible catalysts are used for the elimination reaction of alcohols?
Concentrated H2SO4 (sulfuric acid)
Concentrated H3PO4 (phosphoric acid)
How do alcohols undergo an elimination reaction?
They are heated in the presence of a catalyst
What is the water molecule that is eliminated from an alcohol when making an alkene made up of?
A hydroxyl group and a hydrogen atom that was bonded to a carbon atom adjacent to the hydroxyl carbon
What are the products for the combustion of alcohols?
Water and carbon dioxide
What is the oxidising agent used for the oxidation of alcohols?
Acidified potassium dichromate (VI)
(K2Cr2O7 / H2SO4)
What are the 2 products, in chronological order of formation, for the oxidisation of primary alcohols?
Oxidised to aldehydes and then to carboxylic acid