Q: Which of the following is NOT a constitutional isomer of $$\mathrm{C_5H_{10}}$$ with a conjugated diene system?

$$\mathrm{1,4\text{-}pentadiene}$$

Question 1

Which of the following statements best describes the geometry around an sp2 hybridized carbon atom in ethene ($$\mathrm{C_2H_4}$$)?

Accepted Answer

It is trigonal planar with bond angles of approximately $$120^\circ.$$

Question 2

Which of the following is NOT a constitutional isomer of $$\mathrm{C_5H_{10}}$$ with a conjugated diene system?

Accepted Answer

$$\mathrm{1,4	ext{-}pentadiene}$$

Question 3

Which of the following compounds contains both benzylic and allylic positions?

Accepted Answer

1-Chloro-2-phenylpropene ($$\mathrm{C_6H_5CH=CHCH_2Cl})$$

Question 4

Which of the following is a requirement for a molecule to act as a nucleophile?

Accepted Answer

It must have a pair of electrons available for donation.

Question 5

Which of the following is the best nucleophile in a polar aprotic solvent?

Accepted Answer

$$\mathrm{F^-}$$

Question 6

Which statement correctly describes the effect of electron-withdrawing groups on the reactivity of benzyl chloride in nucleophilic substitution?

Accepted Answer

They increase the reactivity by stabilizing the carbocation intermediate.

Question 7

Which of the following compounds is most likely to undergo a $$1,2-$$hydride shift during carbocation formation?

Accepted Answer

2-Methyl-2-butene

Question 8

Which of the following best explains why tertiary carbocations are more stable than secondary carbocations?

Accepted Answer

Tertiary carbocations have more hyperconjugation and inductive stabilization from surrounding alkyl groups.

Question 9

Which of the following is the correct order of reactivity for alkyl halides in $$\mathrm{S_N1}$$ reactions?

Accepted Answer

Tertiary $$\u003e$$ Secondary $$\u003e$$ Primary $$\u003e$$ Methyl

Question 10

Which of the following statements about the $$E_2$$ elimination mechanism is correct?

Accepted Answer

It requires a strong base and a good leaving group, and the hydrogen and leaving group must be anti-coplanar.

Question 11

Which of the following best describes the product of Markovnikov addition of HBr to 2-methyl-2-butene?

Accepted Answer

2-Bromo-2-methylbutane

Question 12

Which of the following is a correct statement about the $$E_1$$ elimination mechanism?

Accepted Answer

It involves formation of a carbocation intermediate before elimination occurs.

Question 13

Which of the following is the major product when 2-bromopropane is treated with a strong base such as $$\mathrm{KOH} in $$ethanol?

Accepted Answer

Propene

Question 14

Which of the following statements about anti-Markovnikov addition of HBr to an alkene in the presence of peroxides is correct?

Accepted Answer

The bromine atom adds to the less substituted carbon due to a radical mechanism.

Question 15

Which of the following is a correct statement about the oxidation of a benzylic position using $$\mathrm{$$KMnO_4$$}$$?

Accepted Answer

It converts the benzylic carbon to a carboxylic acid regardless of the length of the alkyl chain.

Question 16

Which of the following is the correct order of stability for cyclopropane, cyclobutane, and cyclohexane?

Accepted Answer

Cyclohexane $$\u003e$$ Cyclobutane $$\u003e$$ Cyclopropane

Question 17

Which of the following best explains why cyclopropane is less stable than cyclohexane?

Accepted Answer

Cyclopropane has significant angle strain due to its $$60^\circ$$ bond angles.

Question 18

Which of the following statements about the $$E_a ($$activation energy) curve for a reaction is correct?

Accepted Answer

A lower $$E_a$$ means the reaction proceeds faster.

Question 19

Which of the following is the major product when 2-methyl-2-butene is treated with $$\mathrm{BH_3$}$$ followed by $$\mathrm{H_2O_2}$$ and $$\mathrm{OH^-}$$?

Accepted Answer

2-Methyl-1-butanol

Organic Chemistry Study Notes: Isomerism, Nucleophilicity, Reaction Mechanisms, and Stereochemistry

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