Question 1

Which of the following alcohols can be prepared from a Grignard reagent and ethylene oxide?  &#10;A) only 1&#10;B) only 1 and 2&#10;C) only 1, 2 and 3&#10;D) 1, 2, 3 and 4

Accepted Answer

1 and 2 have primary and secondary Grignard reagents respectively, which can react with ethylene oxide to form primary alcohols. 3 and 4 have tertiary Grignard reagents, which cannot undergo nucleophilic substitution with ethylene oxide.

Question 2

What term describes the process whereby an alkyl halide undergoes reaction with magnesium metal to give an alkylmagnesium bromide (Grignard reagent)?&#10;A) nucleophilic substitution&#10;B) electrophilic addition&#10;C) oxidative addition&#10;D) reductive elimination

Accepted Answer

The process is known as oxidative addition. This is because the magnesium metal is oxidized (loses electrons) while inserting itself into the carbon-halogen bond of the alkyl halide, resulting in the formation of an alkylmagnesium halide, commonly referred to as a Grignard reagent.

Question 3

Which of the following alcohols can be prepared from a Grignard reagent and ethylene oxide?  &#10;A) only 1 and 2&#10;B) only 1 and 4&#10;C) only 1, 2 and 3&#10;D) only 2 and 4

Accepted Answer

only 2 and 4

Question 4

Which of the following compounds is the strongest base? A) CH₃CH₂MgBr B) CH₃CH₂OH C) CH₃CH₂OMgBr D) CH₃CH₃

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Question 5

Which of the following is the best choice of solvent for the formation of phenylmagnesium bromide by the reaction of bromobenzene with magnesium?&#10;A) water&#10;B) methanol&#10;C) diethyl ether&#10;D) acetic acid

Accepted Answer

Diethyl ether is the best choice of solvent for the formation of phenylmagnesium bromide by the reaction of bromobenzene with magnesium. This is because diethyl ether is a non-polar solvent that is inert towards both the reactants and the products, and it has a low boiling point, which makes it easy to remove by evaporation after the reaction is complete. Water, methanol, and acetic acid are all polar solvents that would not be effective for this reaction as they could react with the reactive metal magnesium, and would therefore not be suitable for the synthesis of organometallic compounds.

Question 6

Which of the following is the best choice of solvent for the formation of phenyllithium by the reaction of bromobenzene with lithium?&#10;A) water&#10;B) ethanol&#10;C) tetrahydrofuran&#10;D) acetic acid

Accepted Answer

Tetrahydrofuran (THF) is the best choice of solvent for the reaction of bromobenzene with lithium to form phenyllithium. THF is a polar aprotic solvent that can solvate lithium ions and also has a low boiling point, making it easy to remove from the reaction mixture. Water (A) can react with lithium and is not a suitable solvent for this reaction. Ethanol (B) is a polar solvent but can also react with lithium, the reaction may result in the formation of lithium ethoxide. Acetic acid (D) is a weakly acidic solvent that can protonate phenyllithium and inactivate it.

Question 7

Which of the following bonds has the most ionic character?&#10;A) C-Sn&#10;B) C-Cu&#10;C) C-Zn&#10;D) C-Li

Accepted Answer

Ionic character increases with higher electronegativity difference between the two atoms. Li has a much higher electronegativity compared to carbon, resulting in a more polar bond with more ionic character.

Question 8

Which of the following molecules are deprotonated by ethylmagnesium bromide? A) phenol, PhOH B) propyne, CH₃CºCH C) dimethylamine, (CH₃)₂NH D) all of these

Accepted Answer

Ethylmagnesium bromide is a Grignard reagent, which is a strong base and can deprotonate acidic hydrogens. Phenol, propyne, and dimethylamine all contain acidic hydrogens (phenol has an acidic hydroxyl hydrogen, propyne has an acidic sp-hybridized terminal hydrogen, and dimethylamine has an acidic N-H hydrogen), making them susceptible to deprotonation by ethylmagnesium bromide.

Question 9

What is he change in oxidation state of the metal when magnesium reacts with an alkyl bromide to give an alkylmagnesium bromide (Grignard reagent)?&#10;A) 0 +1&#10;B) 0 +2&#10;C) 0 -1&#10;D) 0 -2

Accepted Answer

In the reaction, magnesium goes from an oxidation state of 0 to +2, since it loses two electrons to form Mg2+. The alkyl bromide, which typically has a halogen (-1) and a carbon (-4) oxidation state, now has a carbon that is less negative (since it has formed a bond with Mg, a less electronegative element) and a halogen that is less negative (since it has lost an electron). Therefore, the oxidation state of the metal (magnesium) has increased from 0 to +2.

Question 10

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 2-methylbutane&#10;B) 3-methyl-1-butanol&#10;C) 3-methyl-2-butene&#10;D) 3-methyl-2-butanol

Accepted Answer

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Question 11

Which of the following compounds is the strongest base? A) NaOH B) NH₃ C) CH₃Li D) CH₃OH

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Question 12

Which of the following bonds has the most ionic character?&#10;A) C-Al&#10;B) C-Hg&#10;C) C-Mg&#10;D) C-Zn

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Question 13

Which combination(s) of alkyl bromide and epoxide can be used to prepare the following product by addition of the Grignard reagent derived from the alkyl bromide to the epoxide?  &#10;A) only 1&#10;B) only 2&#10;C) only 1 and 3&#10;D) only 2 and 4

Accepted Answer

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Question 14

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 2-pentanol&#10;B) pentane&#10;C) 1-pentene&#10;D) (E)-2-pentene

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Question 15

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 16

Which combination(s) of alkyl bromide and epoxide can be used to prepare the following product by addition of the Grignard reagent derived from the alkyl bromide to the epoxide?  &#10;A) only 1&#10;B) only 2&#10;C) only 1 and 3&#10;D) only 2 and 4

Accepted Answer

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Question 17

Which of the following mechanisms accounts for the acid-base reaction of ethylmagnesum bromide with acetylene to give acetylide anion?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 18

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 19

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 20

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 21

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 22

What is the major organic product obtained from the following reaction?&#10;

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Question 23

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 24

What reactive intermediates are involved in the following reaction? A) the trichloromethyl anion (Cl₃C: ^-) and dichlorocarbene (Cl₂C:) B) the trichloromethyl cation (Cl₃C⁺) C) the cyclohexyl carbocation D) the cyclic chloronium ion derived from cyclohexene

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Question 25

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 2-methylheptane&#10;B) 3-methylheptane&#10;C) 2-methyloctane&#10;D) 3-methyloctane

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Question 26

What is the major organic product obtained from the following sequence of reactions?  &#10;A) (E) 6,6-dimethyl-1-hexene&#10;B) (E) 5,5-dimethyl-1-heptene&#10;C) (E) 6,6-dimethyl-1-heptene&#10;D) (E) 6,6-dimethyl-2-heptene

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Question 27

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 28

What is the major organic product obtained from the following sequence of reactions?&#10;

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Question 29

What is the major organic product obtained from the following sequence of reactions?&#10;

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Question 30

What is the major organic product obtained from the following sequence of reactions?&#10;

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Question 31

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 32

What is the major organic product obtained from the following sequence of reactions?  &#10;A) (Z)-6-methyl-2-heptene&#10;B) (E)-4-methyl-2-pentene&#10;C) 2-methylheptane&#10;D) 3-methylheptane

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Question 33

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 34

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 35

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 36

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 37

What is the major organic product obtained from the following reaction?&#10;

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Question 38

Which of the following is not true regarding the carbon atom of the methylene carbene, H₂C: ? A) it is sp² hybridized B) it has a complete octet of valence electrons C) it has a vacant 2p atomic orbital D) it has a lone pair of electrons in an sp² molecular orbital

Accepted Answer

The answer of Which of the following is not true...

Question 39

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 2-iodo-7-methyloctane&#10;B) (E)-7-methyl-1-octene&#10;C) (E)-7-methyl-2-octene&#10;D) (E)-7-methyl-3-octene

Accepted Answer

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Question 40

What is the major organic product obtained from the following reaction?  &#10;A) (E) 2-iodo-2-butene&#10;B) 1-iodo-2-methylpropene&#10;C) methylcyclopropane&#10;D) (E) 2-butene

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Question 41

What is the major organic product obtained from the following reaction?&#10;

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Question 42

What is the major organic product obtained from the following reaction?&#10;

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Question 43

What is the major organic product obtained from the following sequence of reactions?&#10;

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Question 44

What is the major organic product obtained from the following sequence of reactions?&#10;

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Question 45

What is the major organic product obtained from the following reaction?&#10;

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Deck 15: An Introduction to Organometallic Compounds