CHM 219 Module 4/5/7 Exam
Questions With Revised
Correct Detailed Answers
|ALREADY GRADED A+ PASS 2024
>> BRAND NEW VERSION!!
1) Dehydrohalogenation - ANSWER When the reaction occurs
specifically on an alkyl halide substrate. Both H and Halogen are being
eliminated from the substrate molecule.
2) E2 - ANSWER -one step
-biomolecular
-Nucleophile acts as a base and removes the beta H from the beta C, at
the same time the electrons from the C-H bond come down tot for a
C=C bond and break the carbon halogen bond, releasing a halide ion.
3) E1 - ANSWER -several steps
-alkyl halid first undergoes dissociation from the carbocation
intermediate.
,-once formed the carbocation intermediate undergoes elimination by
the nucleophile (acting as base) removing a Beta H from a beta C to
form the C=C
4) Primary Alkyl Halide (RCH2X) - ANSWER Will react by an Sn2
pathway if a good nucleophile (I-, Br-, RS-, NH3, or CN-) is used. There
will be increasing amounts of elimination product from an E2 pathway
as the basicity of the nucleophile increases (HO-, RO-). No Sn1 or E1
pathways are possible for primary substrates.
5) Secondary Alkyl Halide(R2CHX) - ANSWER While all four
mechanistic pathways are possible, typically these substrates will react
by both Sn2 (when weak bases are used) and E2 (when strong bases are
used) pathways to give a mixture of substitution and elimination
products.
6) Tertiary alkyl halide (R3X) - ANSWER Will react by an E2 pathway
when a strong and/or bulky base is used as the nucleophile. When a
weak nucleophile is used (or under acidic conditions) a mixture of
substitution and elimination products will form by Sn1 and E1
mechanisms. No Sn2 pathway is available for tertiary substrates.
7) Organohalides - ANSWER Organic molecules contains Halogen
atoms.
, Ex. Algae, Mollusk, sponges, can be industrially used - solvents,
insecticides, herbicides, cleaning fluids, fire retardants, refrigerants.
Can also be used as inhaled anesthetic.
More important in organic chemistry because of theur reactivity.
8) Two of the most important reaction types typical of organic Halides
are.... - ANSWER Substitution
Elimination
9) Substitution Reaction - ANSWER Replacing the halogen in a
molecule with another atom or functional group.
10) Elimination - ANSWER Removes the halogen and hydrogen
atoms from the original substrate molecule creating an unsaturated
compound.
11) Alkyl halide - ANSWER Aliphatic hydrocarbons that possess one
or more halogen atom substituents.
12) Aryl Halides - ANSWER Aromatic hydrocarbons (benzene rings)
with one or more halogen atoms attached to the ring.
13) Steric Bulk - ANSWER Structural substitution surrounding any
carbon atom that bears a halogen. Methyl, primary, secondary, tertiary.
Questions With Revised
Correct Detailed Answers
|ALREADY GRADED A+ PASS 2024
>> BRAND NEW VERSION!!
1) Dehydrohalogenation - ANSWER When the reaction occurs
specifically on an alkyl halide substrate. Both H and Halogen are being
eliminated from the substrate molecule.
2) E2 - ANSWER -one step
-biomolecular
-Nucleophile acts as a base and removes the beta H from the beta C, at
the same time the electrons from the C-H bond come down tot for a
C=C bond and break the carbon halogen bond, releasing a halide ion.
3) E1 - ANSWER -several steps
-alkyl halid first undergoes dissociation from the carbocation
intermediate.
,-once formed the carbocation intermediate undergoes elimination by
the nucleophile (acting as base) removing a Beta H from a beta C to
form the C=C
4) Primary Alkyl Halide (RCH2X) - ANSWER Will react by an Sn2
pathway if a good nucleophile (I-, Br-, RS-, NH3, or CN-) is used. There
will be increasing amounts of elimination product from an E2 pathway
as the basicity of the nucleophile increases (HO-, RO-). No Sn1 or E1
pathways are possible for primary substrates.
5) Secondary Alkyl Halide(R2CHX) - ANSWER While all four
mechanistic pathways are possible, typically these substrates will react
by both Sn2 (when weak bases are used) and E2 (when strong bases are
used) pathways to give a mixture of substitution and elimination
products.
6) Tertiary alkyl halide (R3X) - ANSWER Will react by an E2 pathway
when a strong and/or bulky base is used as the nucleophile. When a
weak nucleophile is used (or under acidic conditions) a mixture of
substitution and elimination products will form by Sn1 and E1
mechanisms. No Sn2 pathway is available for tertiary substrates.
7) Organohalides - ANSWER Organic molecules contains Halogen
atoms.
, Ex. Algae, Mollusk, sponges, can be industrially used - solvents,
insecticides, herbicides, cleaning fluids, fire retardants, refrigerants.
Can also be used as inhaled anesthetic.
More important in organic chemistry because of theur reactivity.
8) Two of the most important reaction types typical of organic Halides
are.... - ANSWER Substitution
Elimination
9) Substitution Reaction - ANSWER Replacing the halogen in a
molecule with another atom or functional group.
10) Elimination - ANSWER Removes the halogen and hydrogen
atoms from the original substrate molecule creating an unsaturated
compound.
11) Alkyl halide - ANSWER Aliphatic hydrocarbons that possess one
or more halogen atom substituents.
12) Aryl Halides - ANSWER Aromatic hydrocarbons (benzene rings)
with one or more halogen atoms attached to the ring.
13) Steric Bulk - ANSWER Structural substitution surrounding any
carbon atom that bears a halogen. Methyl, primary, secondary, tertiary.
