Organic Chemistry Exam Questions with all Correct Answers
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Course
Organic Chemistry for Life
Institution
Organic Chemistry For Life
Organic Chemistry Exam Questions with all Correct Answers 1-bromopropane H-NMR spectrum - ANSWER-
.Absolute COnfiguration - ANSWER-Assign priority to all four substituents based on molecular weight, with higher molecular weight at...
Organic Chemistry Exam Questions with all
Correct Answers
1-bromopropane H-NMR spectrum - ANSWER-
.Absolute COnfiguration - ANSWER-Assign priority to all four substituents based on molecular weight, with
higher molecular weight atoms receiving higher priority.
Rotate the lowest priority substituent to the back (i.e., into the page).
If proceeding in order from one to three requires a clockwise motion, the absolute configuration is R;
If the smallest atom is coming out of the page, you reverse it, so ex- if it is R, but smallest atom is out of the
page at 4, reverse it to S, and i'll be correct.
If proceeding in order from one to three requires a counter-clockwise motion, the absolute configuration is S.
Remember how things change if the heaviest is into the page, it is always the reverse
The lowest priority R group is pointed away from you. You then consider the priority of the other three R
groups. If
that priority descends in a clockwise fashion, the molecule is R. If it descends counterclockwise, then the chiral
center is S.
.Acetal - ANSWER-An acetal is a functional group with the following connectivity R2C(OR')2, where both R'
groups are organic fragments.
.Acetic Formic Anhydride - ANSWER-
,.Acetoacetic Ester Synthesis - ANSWER-Formation of a ketone from a β-keto ester.
o STEPS:
1) A base abstracts the acidic alpha hydrogen, leaving a carbanion.
2) The carbanion attacks an alkyl halide (R-X), resulting in addition of the -R group to the alpha carbon.
3) Hot acid during workup causes loss of the entire -COOR group
.Acetyl - ANSWER-In organic chemistry, acetyl is a functional group, the acyl with chemical formula CH3CO. It is
sometimes represented by the symbol Ac (not to be confused with the element actinium). The acetyl group
contains a methyl group single-bonded to a carbonyl.
.Acid Chlorides - ANSWER-Any Compound containing a carbonyl with a chlorine substituent on the carbonyl
carbon
Nomenclature
- oyl chloride for the ending, ex- propanoyl chloride
.Acidity - ANSWER-ALways look at the stability of the conjugate base
STability or lack thereof will be affected by EDG or EWG.
Alcohols are weaker acids than water due to donating effect of the R groups
,RESONANCE STABILIZATION, if there is resonance, it makes it more acidic
.Acyl - ANSWER-a functional group derived by the removal of one or more hydroxyl groups from an oxoacid,[1]
including inorganic acids. It contains a double bonded oxygen atom and an alkyl group.
.Addition of Amines to Carbonyls (Formation of Enamines and Imines) - ANSWER-o Amines add to aldehydes
and ketones to form imines and enamines.
o STEPS:
1) The amine acts as a nucleophile, attacking the electrophilic carbonyl carbon.
2) The oxygen is protonated twice, creating the good leaving group water.
3) A base abstracts a hydrogen from the nitrogen and kicks off water in an E2 mechanism. This forms either an
imine or an enamine (depending on the substitution pattern of the nitrogen).
• Primary amines yield imines
• Secondary amines yield enamines
• Tertiary amines do not react.
.Affinity Chromatography - ANSWER-Used to isolate a specific molecule or product based on a very specific
affinity or binding interaction
Example- Molecules in mixture react via acid-base neutralization with molecules on the column. To elute the
bound target molecule, one must disrupt the binding interaction. This can be done with a salt solution or a
chemical reversal of the reaction bound to the target to the column.
, .Alcohol - ANSWER-
.Alcohol Acidity - ANSWER-Less acidic than water
Acidity increases form tertiary to secondary to primary, meaning a primary is mostly like to give it's H
Both trends are explained by the fact that alkyl substituents are weak electron donating groups. When we look
at the conjugate base of water there are no alkyl groups donating electron density to destabilize the oxygen
with additional negative charge.
With primary, secondary and tertiary alcohols there are one, two and three donating groups respectively.
Therefore, tertiary alcohols are the least stable because the conjugate base in that case is destabilized to the
greatest degree by induction. Carboxylic acids experience the exact opposite effect because the carbonyl is a
strong electron withdrawing group. Further (and even more importantly) the conjugate base in the case of a
carboxylic acid is stabilized by resonance.
.Alcohols - ANSWER-Any species with -PH funcitonal group
Can act as nucleophiles or as lewis acidwhen oxidized to a carbonyl group
Nomenclature- Alcohols have -ol suffix, butanol, cycloheanol, 1,3-hexanediol
Boiling Point- Goes up with increasing molecular weight and decreases with increased branching
Melting Point- Goes up with polarity and H-bonding and the effect of branching on melting point depends
.Aldehyde - ANSWER-
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