Question 1

Determine whether the $$\sigma$$ bond or the $$\pi$$ bond has the more effective orbital overlap in a carbon–carbon double bond.

Accepted Answer

$$\sigma$$ bond has a more effective orbital overlap than the $$\pi$$ bond

Question 2

Rank the molecules below from most to least water soluble: (A) ethanol, (B) 2-butanol, (C) 1-chloropropane, (D) pentane.

Accepted Answer

A \u003e B \u003e C \u003e D

Question 3

Compared to butane and other alkanes, there is no free rotation around any C–C bonds in cyclobutane. Provide a brief explanation.

Accepted Answer

There is no free rotation around any C–C bonds in cyclobutane because they are constrained in a ring structure.

Question 4

Pick out the most stable conjugate base among the following: (a) 2-oxopiperidin-1-ide, (b) cyclohexanolate. Which structural feature did you analyze?

Accepted Answer

Structure (a) is the more stable conjugate base. (ii) Resonance.

Question 5

Write the appropriate systematic name for the following compound: (structure with Br and Cl on a cyclohexane ring, with ethyl and dimethyl substituents).

Accepted Answer

5-bromo-1-chloro-4-ethyl-2,2-dimethylcyclohexane

Question 6

Provide the name of the following alkyne using IUPAC rules: (structure with three double bonds and one triple bond, with a chlorine substituent).

Accepted Answer

(5S,7Z,9E)-5-chlorododeca-7,9-dien-1-yne

Question 7

Some pairs of structures are given. Recognize each of these pairs as different entities or resonance forms of the same compound: (a) nitrile/ketone, (b) two pentanones, (c) isopropanol/acetone).

Accepted Answer

Different compounds, Resonance forms, Different compounds

Question 8

Explain why pyrrole (129 $$^\circC) $$boils at a higher temperature than $$N-$$methyl pyrrole (112 $$^\circC).$$

Accepted Answer

Pyrrole can form hydrogen bonds which is why it has a higher boiling point than $$N-$$methyl pyrrole

Question 9

Determine the name for the given cycloalkane using the IUPAC nomenclature system: (structure with two isopropyl, one ethyl, and one methyl substituent on cyclohexane).

Accepted Answer

2-ethyl-4,5-diisopropyl-1-methylcyclohexane

Question 10

The following is the structure of citric acid. (i) Determine if the given structure is a carboxylic acid. (ii) Compare the acidic strength of citric acid with lactic acid. Citric acid and lactic acid have $$pK_a$$ values of 3.13 and 3.86, respectively.

Accepted Answer

Citric acid is a carboxylic acid. Citric acid is a slightly stronger acid than lactic acid.

Question 11

A synthesis is carried out with a Grignard reagent containing radioactive carbon ($$^{14}C) to $$get the isomers shown. Predict whether the final product would be chiral or achiral if we performed the same synthesis without using any $$^{14}C-$$labeled substrate.

Accepted Answer

Product will be racemic.

Question 12

Which of the reactants is the Lewis acid and which one is the Lewis base in the reaction given below? (2-methylbut-2-ene and $$Cl_2)$$

Accepted Answer

2-methylbut-2-ene is a Lewis base and chlorine is a Lewis acid.

Question 13

Below are the enantiomers of 1,2-dimethylazetidine. One group around nitrogen is a lone pair, but these two enantiomers can be separated. Explain why.

Accepted Answer

The enantiomers can be separated because the nitrogen in the ring cannot meet the $$120^\circ$$ bond angle requirement for amine inversion, preventing the interconversion of the enantiomers.

Question 14

In the given reaction, if the temperature is increased, which side of the reaction, if any, would be favored? (Aldol condensation)

Accepted Answer

The reverse reaction would be more favored.

Question 15

Which of the following structures has a better leaving group? Justify your answer. (a) $$ROH$$, (b) $$ROH_2$$^+$$)

Accepted Answer

Structure (b) has a better leaving group because the loss of the leaving group forms a weaker (more stable) base that is neutral.

Organic Chemistry Multiple Choice and Conceptual Guidance

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