Question 1

Which of the following best describes the polarization of the carbon–metal bond in organometallic compounds?

Accepted Answer

The bond is polarized towards carbon, making carbon nucleophilic.

Question 2

Which of the following compounds is NOT considered an organometallic compound?

Accepted Answer

Sodium ethoxide ($$\mathrm{C_2H_5ONa})$$

Question 3

What is the main role of magnesium in the preparation of Grignard reagents?

Accepted Answer

It inserts into the carbon–halogen bond, forming $$\mathrm{R-MgX}.$$

Question 4

Which of the following statements about the preparation of organolithium compounds is correct?

Accepted Answer

Lithium donates two electrons to the organic halide ($$\mathrm{RX}) to $$form $$\mathrm{RLi}.$$

Question 5

Which of the following best explains why organolithium and Grignard reagents must be kept away from water during reactions?

Accepted Answer

They are strong Brønsted bases and will react with water to form alkanes.

Question 6

Which of the following is the correct product when methylmagnesium bromide ($$\mathrm{CH_3MgBr}) $$reacts with acetone ($$\mathrm{(CH_3$)_2CO}) $$followed by acid workup?

Accepted Answer

tert-Butanol ($$\mathrm{(CH_3$)_3COH})$$

Question 7

In the nomenclature of organometallic compounds, which part is considered the parent?

Accepted Answer

The metal atom

Question 8

Which of the following statements about the nucleophilic addition of Grignard reagents to carbonyl compounds is correct?

Accepted Answer

The Grignard reagent acts as a nucleophile and attacks the carbonyl carbon.

Question 9

Which of the following best describes the mechanism for the formation of organomagnesium compounds from alkyl halides?

Accepted Answer

A single-electron transfer forms a radical anion intermediate.

Question 10

Which of the following statements about the basicity of organolithium and Grignard reagents is TRUE?

Accepted Answer

They are strong Brønsted bases and can deprotonate water and alcohols.

Question 11

Which of the following is a common use of n-butyllithium in organic synthesis?

Accepted Answer

To prepare less basic organometallic compounds by deprotonation

Question 12

A chemist wants to replace a bromine atom in bromobenzene ($$\mathrm{C_6H_5Br}) $$with a deuterium atom. Which sequence of reagents would accomplish this transformation?

Accepted Answer

1. $$\mathrm{Mg}$$, ether; 2. $$\mathrm{D_2O}$$

Question 13

Which of the following best explains why Grignard reagents are typically prepared in dry ether?

Accepted Answer

Ether stabilizes the Grignard reagent and prevents reaction with moisture.

Question 14

Which of the following carbonyl compounds will react fastest with a Grignard reagent under identical conditions?

Accepted Answer

Formaldehyde ($$\mathrm{H_2C=O})$$

Question 15

Which of the following is the correct product when phenylmagnesium bromide ($$\mathrm{C_6H_5MgBr}) $$reacts with benzaldehyde ($$\mathrm{C_6H_5CHO}) $$followed by acid workup?

Accepted Answer

1,2-Diphenylethanol ($$\mathrm{C_6H_5CH(OH)C_6H_5})$$

Question 16

Which of the following statements about the character of the C–M bond in organometallic compounds is correct?

Accepted Answer

It often has both ionic and covalent character.

Question 17

A student attempts to prepare ethylmagnesium bromide ($$\mathrm{C_2H_5MgBr}) $$from bromoethane and magnesium in water. What is the most likely outcome?

Accepted Answer

The Grignard reagent will react with water to form ethane ($$\mathrm{C_2H_6}).$$

Question 18

Which of the following best describes the role of organolithium and Grignard reagents in the synthesis of alcohols?

Accepted Answer

They act as nucleophiles, attacking the electrophilic carbonyl carbon.

Question 19

Which of the following is a key difference between the preparation of organolithium and organomagnesium compounds?

Accepted Answer

Lithium donates two electrons to the organic halide, while magnesium inserts into the C–X bond.

Organometallic Compounds: Structure, Nomenclature, Preparation, and Reactivity

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