Question 1

Which of the following best describes a nucleophile in organic chemistry?

Accepted Answer

An electron-rich species that donates a pair of electrons to an electrophile.

Question 2

Which of the following is the correct balanced equation for the complete combustion of pentane ($$C_5H_{12}$$)?

Accepted Answer

$$2C_5H_{12} + 16O_2 \rightarrow 10CO_2 + 12H_2O$$

Question 3

During the free-radical halogenation of alkanes, which step is responsible for generating the first free radicals?

Accepted Answer

Initiation

Question 4

Which of the following statements about the selectivity of halogenation is correct?

Accepted Answer

Bromination is more selective than chlorination.

Question 5

In the context of organic reaction mechanisms, what does a double-headed curved arrow represent?

Accepted Answer

The movement of two electrons.

Question 6

Which of the following is a correct example of a substitution reaction?

Accepted Answer

$$CH_4$$ + $$Cl_2$$ \xrightarrow{hv} CH_3Cl + HCl$$

Question 7

Which of the following best describes a primary carbon atom in an alkane?

Accepted Answer

A carbon atom bonded to only one other carbon atom.

Question 8

Which of the following is the correct order of stability for alkyl radicals?

Accepted Answer

Tertiary \u003e Secondary \u003e Primary \u003e Methyl

Question 9

Which of the following best explains why alkanes are generally unreactive under normal conditions?

Accepted Answer

They have strong C–H and C–C sigma bonds and lack functional groups.

Question 10

In a free-radical halogenation reaction, which of the following is a termination step?

Accepted Answer

$$\cdot CH_3$ + \cdot CH_3$ \rightarrow C_2H_6$$

Question 11

Which of the following is a correct description of an electrophile?

Accepted Answer

An electron-poor species that can accept a pair of electrons.

Question 12

Which of the following best describes the difference between a reaction and a mechanism in organic chemistry?

Accepted Answer

A reaction shows only the reactants and products, while a mechanism shows the stepwise process of bond breaking and forming.

Question 13

Which of the following is an example of an elimination reaction?

Accepted Answer

$$CH_3CH_2Br + KOH \rightarrow CH_2$=CH_2$ + KBr + H_2O$$

Question 14

Which of the following statements about the combustion of alkanes is correct?

Accepted Answer

Combustion of alkanes is exothermic and produces $$CO_2$$ and $$H_2O.$$

Question 15

Which of the following best describes a homolytic bond cleavage?

Accepted Answer

Each atom involved in the bond takes one electron, forming two radicals.

Question 16

Which of the following is a correct example of an addition reaction?

Accepted Answer

$$CH_2$$=$$CH_2$$ + $$H_2$$ \rightarrow CH_3CH_3$$

Question 17

Which of the following statements about the use of curved arrows in organic mechanisms is correct?

Accepted Answer

A single-headed arrow shows the movement of one electron, while a double-headed arrow shows the movement of two electrons.

Question 18

Which of the following is the correct classification for the carbon atom in $$CH_3CH_2CH_3 ($$the middle carbon)?

Accepted Answer

Secondary carbon

Question 19

Which of the following is a correct propagation step in the free-radical chlorination of methane?

Accepted Answer

$$\cdot Cl + CH_4$ \rightarrow HCl + \cdot CH_3$

Question 20

Which of the following best explains why tertiary hydrogens are more reactive in free-radical halogenation than primary hydrogens?

Accepted Answer

Tertiary radicals formed are more stable due to hyperconjugation and inductive effects.

Chemical Reactivity in Organic Chemistry: Major Reactions, Mechanisms, and Alkanes

Study Guide - Practice Questions