UTA ORGANIC CHEMISTRY I (BUGARIN) - TEST TWO
QUESTIONS AND CORRECT DETAILED ANSWERS
(VERIFIED ANSWERS) ALREADY GRADED A+
Substitution Ans✓✓✓When treated with a nucleophile, an alkyl halide
undergoes a _____ reaction where the nucleophile replaces the halogen.
Elimination Ans✓✓✓When treated with a base, an alkyl halide
undergoes a _____ reaction where a pi bond (double bond) is created.
Strong nucleophile; primary/methyl substrate; polar aprotic solvent;
inversion of configuration Ans✓✓✓In summation: SN2 reactions
Weak nucleophiles; tertiary substrate; polar protic solvent (hydrogen
bonding); retention of configuration (racemization) Ans✓✓✓In
summation: SN1 reactions
Strong base (big molecule); tertiary substrate; polar aprotic solvent;
requires transferrable proton and leaving group to be anti-periplanar.
Ans✓✓✓In summation: E2 reactions
Weak base; tertiary substrate; polar protic solvent; produces unequal
mixes of enantiomers Ans✓✓✓In summation: E1 reactions
The greater electronegativity of the halide withdraws electron density of
the adjacent carbon atom and renders it electrophilic. Ans✓✓✓How
does the induction effect created by a halide encourage a reaction?
,Conjugate bases Ans✓✓✓Good leaving groups are the _____ of strong
acids with pKa < 0
The stronger the acid, the weaker the conjugate base and the better said
base functions as a leaving group. Ans✓✓✓Repeat: The stronger the
acid, the weaker the conjugate base and and the better said base
functions as a leaving group.
Stable bases Ans✓✓✓Weak bases are the most _____
Carbon atom directly attached to halogen. Only one in a molecule.
Ans✓✓✓Identify the alpha position of an alkyl halide.
Carbon atoms attached to the alpha carbon. Ans✓✓✓Identify the beta
position of an alkyl halide.
Whether the alkyl halide is primary (1 R-group), secondary (2 R-groups)
or tertiary (3 R-groups) Ans✓✓✓What do the beta positions of an alkyl
halide signify?
Concerted; both nucleophilic attacks/proton transfers and loss of the
leaving group occur in a single step Ans✓✓✓SN2 and E2 reactions
feature _____ mechanisms
, Stepwise; the steps occur with a carbocation intermediate. Ans✓✓✓SN1
and E1 reactions feature _____ mechanisms
Bimolecular Ans✓✓✓Concerted reactions are _____ because they
involve the simultaneous collision of molecules
The configuration is inverted, which requires that the nucleophile must
attack from the backside. Ans✓✓✓What happens in an SN2 reaction
where the alpha position is a chiral center?
Because according to MO theory, electron density flows from HOMO to
the LUMO; at the front, a node will be encountered and the lack of an
overlap prevents the reaction. Ans✓✓✓Why can nucleophiles only
attack from the backside of the molecule?
Stereospecific Ans✓✓✓SN2 and E2 reactions are said to be _____
because the configuration of the product is dependent on the
configuration of the starting material.
Constituents at the alpha or beta positions, which slow the reaction.
Alpha substituents are more harmful to the rate. Ans✓✓✓The rate of an
SN2 reaction is very sensitive to the presence of _____
Primary or methyl Ans✓✓✓SN2 reactions occur with _____
substituents
QUESTIONS AND CORRECT DETAILED ANSWERS
(VERIFIED ANSWERS) ALREADY GRADED A+
Substitution Ans✓✓✓When treated with a nucleophile, an alkyl halide
undergoes a _____ reaction where the nucleophile replaces the halogen.
Elimination Ans✓✓✓When treated with a base, an alkyl halide
undergoes a _____ reaction where a pi bond (double bond) is created.
Strong nucleophile; primary/methyl substrate; polar aprotic solvent;
inversion of configuration Ans✓✓✓In summation: SN2 reactions
Weak nucleophiles; tertiary substrate; polar protic solvent (hydrogen
bonding); retention of configuration (racemization) Ans✓✓✓In
summation: SN1 reactions
Strong base (big molecule); tertiary substrate; polar aprotic solvent;
requires transferrable proton and leaving group to be anti-periplanar.
Ans✓✓✓In summation: E2 reactions
Weak base; tertiary substrate; polar protic solvent; produces unequal
mixes of enantiomers Ans✓✓✓In summation: E1 reactions
The greater electronegativity of the halide withdraws electron density of
the adjacent carbon atom and renders it electrophilic. Ans✓✓✓How
does the induction effect created by a halide encourage a reaction?
,Conjugate bases Ans✓✓✓Good leaving groups are the _____ of strong
acids with pKa < 0
The stronger the acid, the weaker the conjugate base and the better said
base functions as a leaving group. Ans✓✓✓Repeat: The stronger the
acid, the weaker the conjugate base and and the better said base
functions as a leaving group.
Stable bases Ans✓✓✓Weak bases are the most _____
Carbon atom directly attached to halogen. Only one in a molecule.
Ans✓✓✓Identify the alpha position of an alkyl halide.
Carbon atoms attached to the alpha carbon. Ans✓✓✓Identify the beta
position of an alkyl halide.
Whether the alkyl halide is primary (1 R-group), secondary (2 R-groups)
or tertiary (3 R-groups) Ans✓✓✓What do the beta positions of an alkyl
halide signify?
Concerted; both nucleophilic attacks/proton transfers and loss of the
leaving group occur in a single step Ans✓✓✓SN2 and E2 reactions
feature _____ mechanisms
, Stepwise; the steps occur with a carbocation intermediate. Ans✓✓✓SN1
and E1 reactions feature _____ mechanisms
Bimolecular Ans✓✓✓Concerted reactions are _____ because they
involve the simultaneous collision of molecules
The configuration is inverted, which requires that the nucleophile must
attack from the backside. Ans✓✓✓What happens in an SN2 reaction
where the alpha position is a chiral center?
Because according to MO theory, electron density flows from HOMO to
the LUMO; at the front, a node will be encountered and the lack of an
overlap prevents the reaction. Ans✓✓✓Why can nucleophiles only
attack from the backside of the molecule?
Stereospecific Ans✓✓✓SN2 and E2 reactions are said to be _____
because the configuration of the product is dependent on the
configuration of the starting material.
Constituents at the alpha or beta positions, which slow the reaction.
Alpha substituents are more harmful to the rate. Ans✓✓✓The rate of an
SN2 reaction is very sensitive to the presence of _____
Primary or methyl Ans✓✓✓SN2 reactions occur with _____
substituents
