Question 1

Which Newman projection below represents the anti conformation of butane?

Accepted Answer

The conformation where the two methyl groups are 180° apart.

Question 2

Given the following energy diagrams, which one corresponds to a one-step mechanism?

Accepted Answer

The diagram with a single transition state and no intermediates.

Question 3

Which of the following Newman projections represents a gauche conformation for butane?

Accepted Answer

The conformation where the two methyl groups are 60° apart.

Question 4

Which Fischer projection below represents a meso compound?

Accepted Answer

The compound with two chiral centers and an internal plane of symmetry.

Question 5

What is the relationship between the two Fischer projections shown below?

Accepted Answer

They are enantiomers.

Question 6

For the reaction $$\mathrm{(CH_3$)_3CBr \rightarrow (CH_2$)=C(CH_3$)_2 + HBr}$$, what is the sign of $$\Delta S$$?

Accepted Answer

Positive

Question 7

Which of the following energy diagrams exhibits the largest activation energy?

Accepted Answer

The diagram with the highest peak relative to the starting material.

Question 8

Which process will have a value of $$K_{eq}$$ that is greater than 1?

Accepted Answer

The process where the products are lower in energy than the reactants.

Question 9

Which process will have a positive $$\Delta G$$?

Accepted Answer

The process where the products are higher in energy than the reactants.

Question 10

Which process will have a $$\Delta G$$ that is roughly equal to 0?

Accepted Answer

The process where the products and reactants are at the same energy.

Question 11

Using the periodic table provided, which element is the most electronegative?

Accepted Answer

Fluorine

Question 12

Which of the following best describes the transition state for the E2 elimination of tert-butyl bromide?

Accepted Answer

A structure where the C-H and C-Br bonds are both partially broken and the C=C bond is partially formed.

Question 13

Which of the following is the correct rate law for an $$S_N2$$ reaction between $$\mathrm{CH_3I}$$ and $$\mathrm{NaOH}$$?

Accepted Answer

$$\mathrm{Rate = k[CH_3I][NaOH]}$$

Question 14

Given the specific rotation of $$(S)-2-$$bromobutane is $$+10.5^\circ$$, what is the specific rotation of a racemic mixture of 2-iodobutane?

Accepted Answer

$$0$$

Question 15

Which of the following is a constitutional isomer of butane?

Accepted Answer

Isobutane ($$\mathrm{2-methylpropane})$$

Question 16

Which of the following cycloalkanes has the most angle strain?

Accepted Answer

Cyclopropane

Question 17

Which of the following is the most stable carbocation?

Accepted Answer

Tertiary carbocation

Question 18

Which of the following represents cis-1-bromo-3-ethylcyclohexane?

Accepted Answer

The structure where both substituents are on the same side of the ring.

Question 19

Which of the following is an example of a nucleophilic center in organic molecules?

Accepted Answer

An oxygen atom in an alcohol group ($$-OH)$$

Organic Chemistry II Exam 2 Review – Step-by-Step Guidance

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