organic chem 7,8 Flashcards
what is the difference between primary 1º secondary 2º and tertiary 3º alcohols?
depends on the number of R groups that is attached to the carbon with the OH
how do you name an alcohol?
start with the substituents that are the closest to the hydroxyl group and name from that side onwards
why do alcohols and phenols have higher boilings points than expected?
due to hydrogen bonding (O- —- H+ )
what determines the solubility of alcohol in water?
solubility decreases as the size of the alkyl group increases (methyl, ethyl etc..)
compounds with a larger Ka and smaller pKa are more —?
acidic
compounds with smaller Ka and larger pKa are less —-?
acidic
what does the constant Ka (acidity constant) represent
the strength of any acid in water
what does the acidity of alcohols look like?
very low acidity
what is the acidity of water like compared to phenols?
phenols are more acidic compared to alcohols
what happens in a dehydration reaction?
elimination of H2O from alcohol and a new pi bond (double bond) forms an alkene
what is the condition for dehydration in alcohols?
carried out using conc H2SO4 and other strong acids.
what is the trend for rate of an alcohol being dehydrated?
the more substituents alcohols have, they dehydrate more easily.
1o alcohols are more difficult to dehydrate. They require high temperatures in concentrated H2SO4
2o alcohols require lower temperatures
3o alcohols are the easiest to dehydrate and undergo dehydration only slightly above room temperature
When the dehydration of an alcohol can produce more than one different double bond, Which double bond would be major product?
the most substituted double bond would form. the side of the bond that has OH which has more carbons on that side. ZAITSEFF’S RULE
HOW IS A MORE STABLE CARBOCATION INTERMEDIATE FORMED WHEN ADDING H-X
H adds to the less substituted Carbon and the other atom X adds to the other carbon.
what does major product mean ?
more of that product is made as it is more stable
what are the properties of ethers? (5)
-polar compounds
(+) C-O (-)
-WEAK IMF = LOW BP
-LOW CHEMICAL REACTIVITY
-GOOD SOLVENTS FOR POLAR AND NON POLAR COMPOUNDS IN CHEMICAL REACTIONS
-FLAMMABLE
DO ETHERS ACCEPT OR DONATE IN HYDROGEN BONDS WITH -OH OR -NH AS EHTERS CANNOT H-BOND WITH EACH OTHER?
HYDROGEN BOND ACCEPTORS.
what is a bronsted Lowry acid?
bronsted Lowry acid is proton DONOR
what is a bronsted Lowry base?
bronsted Lowry BASE is a proton ACCEPTOR
WHAT IS A PROTON REPRESENTED BY ACCORDING TO HYDROGEN?
H+
WHAT ARE THE PROPERTIES OF BRONSTED LOWRY BASES?
-CONTAINS A LONE PAIR OF PI BOND
-THE NET CHARGE MAY BE 0 OR -
examples of bronsted Lowry acid?
hcl
h2so4
hso4-
h20
h3o+
ch3co2h
example of bronsted Lowry base?
:nh3
oh-
nh2:
ch3o:-
ch2=ch2
what’s the equation for pKa?
pKa = -log Ka
equation for Ka?
Ka = [H+][A-] / [HA]
WHAT IS A CONJUGATE BASE?
COMPOUND THAT HAS TO ACCEPT A PROTON TO GO BACK TO WHAT IT WAS AT THE FORWARD REACTION
WHAT IS A CONJUGATE ACID?
COMPOUND THAT HAS TO DONATE A PROTON IN ORDER TO RETURN BACK TO WHAT IT WAS IN THE FORWARD REACTION.
WHAT IS RESONANCE?
Resonance is a way of describing delocalised electrons within certain molecules
WHAT DOES LOW pKa mean?
stronger acid
when does the acidity of H-A increase?
when electron withdrawing group is pulled from the negative charge (A-) towards H+
The more electronegative the group X, the more it pulls electron density towards it the weaker the corresponding acid should be. WHY?
as it would be harder to dissociate and break them apart.
what increases acid strength of carboxylic acids?
increasing number of halogens attached to carbon next to the carboxylic acid increase the acid strength.
how does the inductive effect affect the strength of carboxylic acid?
negative inductive effect increase the strength of an acid.
they do so most effectively when closest to the carboxylic acid
