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Organic Chem 4 Portage Learning Exam 2024/2025 Questions With Completed & Verified Solutions.
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Organic Chem 4 Portage Learning Exam 2024/2025 Questions With Completed & Verified Solutions.
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Organic Chem 4 Portage Learningconcerted
The chemical term for a one-step mechanism
Because two molecules, namely, the nucleophile AND the substrate, are directly involved in the
key step (the only step) of the mechanism.
Thus, increasing the concentration of either the nucleophile or substrate will increase the rate of
the reaction.
The number 2 (second order overall in terms of the reaction kinetics) in the label of the
mechanism indicates the reaction is bimolecular for this reason.
Why is the number 2 is used to label the SN2 mechanism?
Increasing the concentration of either the nucleophile or substrate will increase the rate of the
reaction.
What would happen if either the concentration of nucleophile or substrate increase?
SN2 reactions depend on a strong nucleophile. Strong nucleophiles typically are negatively
charged and, as a result, seek positive charge more strongly than neutral molecules. An
example is hydroxide ion (HO-) versus water (H2O). While both are nucleophiles, hydroxide is a
much stronger nucleophile than water. An SN2 reaction that occurs in pure water would be
slower than one that happens in aqueous sodium hydroxide for this reason.
How does the strength of the nucleophile impact the SN2 mechanism path?
bulky
The SN1 mechanism typically occurs when the alkyl halide is _____, meaning 3° and some 2°
halides (when the alkyl groups attached to the leaving group carbon are large).
True
True or False: Since the rate of an SN1 reaction is not at all affected by the nucleophile, none of
the characteristics of the nucleophile (size, strength, concentration, electronegativity, etc.) have
an impact on the rate of an SN1 reaction.
, Larger nucleophiles are more efficient at backside attacks than small nucleophiles. Thus,
bisulfide (HS-) as a nucleophile would react faster than hydroxide (HO-) due to the larger sulfur
atom (with all other things being equal)
How does the size of the nucleophile impact the SN2 mechanism path?
The nucleophile uses a lone pair of electrons to bond to the substrate, so if the atom that holds
the lone pair is very electronegative, it tends to hold those electrons tightly and thus, is less
nucleophilic. Within any given row of the periodic table, electronegativity increases to the right;
therefore (as one example), ammonia (NH3) is a stronger nucleophile than water (H2O)
because N is less electronegative than O.
How does the electronegativity of the nucleophilic atom impact the SN2 mechanism path?
Mechanisms
show the flow of electrons between molecules and ions as the reagents are converted to
products.
Curved arrow notation
________ is used to draw mechanisms in organic chemistry, just like when showing electron
resonance.
structure
The mechanism observed for a particular reaction depends (in large part) on the _______ of the
alkyl halide substrate in the reaction.
SN2
This reaction mechanism occurs in a single step
"backside attack".
In an SN2 mechanism, The nucleophile uses a lone pair of electrons to begin making a bond to
the carbon. Simultaneously, the bond between the carbon and leaving group begins to break.
This process is known as a _______
By their nature, alkyl halides and nucleophiles tend to be polar species (nucleophiles can be
fully anionic as well) and, thus, require polar solvents to dissolve them. Since the SN2
mechanism relies on the nucleophile being uninhibited during backside attack, SN2 reactions
are faster when solvents are not strongly attracted to the nucleophile. The best solvents for SN2
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