Organic Chemistry II Formative Test Practice Example - Aromatic Compounds PDF

Organic Chemistry II Formative Test Practice Example - Aromatic compounds What did August Kekulé propose in 1872 regarding the structure of benzene? A. A linear chain of carbon atoms B. A ring of six sp2 hybrid carbon atoms C. A mixture of single and triple bonds...

Organic Chemistry II Formative Test Practice Example - Aromatic compounds What did August Kekulé propose in 1872 regarding the structure of benzene? A. A linear chain of carbon atoms B. A ring of six sp2 hybrid carbon atoms C. A mixture of single and triple bonds D. A hybrid of two equivalent Kekulé structures How are the C-C bonds in benzene described in the hybrid structure? A. Single bonds B. Double bonds C. Triple bonds D. Something in between single and double bonds What is the bond angle in benzene? A. 90° B. 120° C. 180° D. 60° Why are the carbon-carbon bond lengths in benzene unique? A. They are longer than single-bond lengths B. They are shorter than double-bond lengths C. They are equal in length D. They vary depending on the position in the ring How many conjugated double bonds does benzene contain? A. One B. Two C. Three D. Four What happens when bromine is added to most alkenes in carbon tetrachloride? A. The red bromine color remains B. The red bromine color disappears C. A yellow color appears D. The solution turns green How does benzene react when bromine is added to it? A. The red bromine color disappears B. No reaction occurs, and the red bromine color remains C. A yellow color appears D. The solution turns green What type of reaction does benzene undergo with bromine? A. Addition B. Substitution C. Elimination D. Polymerization What effect does the addition of a catalyst like ferric bromide have on the reaction between bromine and benzene? A. Speeds up the addition reaction B. Prevents any reaction from occurring C. Causes the bromine color to disappear slowly D. Turns the solution green What is the result of the reaction between bromine, benzene, and a catalyst like ferric bromide? A. Addition of bromine across the double bond B. Formation of HBr gas only C. Substitution of a bromine atom for a hydrogen D. Elimination of all double bonds What term is used to describe cyclic hydrocarbons with alternating single and double bonds? A. Alkenes B. Alkynes C. Annulenes D. Arenes Which compound is an example of annulene? A. Benzene B. Cyclobutadiene C. Cyclohexane D. Cyclooctatetraene Why were compounds like cyclobutadiene and cyclooctatetraene mistakenly expected to be aromatic? A. Due to their lack of resonance structures B. Because they have alternating single and double bonds C. Because they contain triple bonds D. Because they lack stability How are the carbon atoms in benzene hybridized? A. sp hybridized B. sp³ hybridized C. sp² hybridized D. dsp² hybridized How many π electrons does benzene have? A. Four B. Five C. Six D. Seven What contributes to the delocalized π electron system in benzene? A. Hybridized s orbitals B. Unhybridized p orbitals C. Hybridized d orbitals D. Hybridized sp³ orbitals What type of orbitals form the sigma (σ) bonds in benzene? A. s orbitals B. p orbitals C. d orbitals D. sp² hybrid orbitals Which orbitals in benzene contribute to its stability? A. π4*, π5*, π6* B. π1, π2, π3 C. σ orbitals D. s orbitals According to Hückel’s rule, how many π electrons must an aromatic hydrocarbon like benzene have? A) 4n B) 4n + 2 C) 2n D) 2n + 2 How many π bonds does benzene have, leading to 6 π electrons? A) 1 B) 2 C) 3 D) 4 What is the value of n when the equation 4n + 2 = 6 is solved? A) 0 B) 1 C) 2 D) 3 Which of the following systems are classified as aromatic based on the number of π electrons? A) 4 and 8 B) 4 and 6 C) 6 and 10 D) 8 and 12 What is the classification for systems with 4 and 8 π electrons if they are planar? A) Aromatic B) Antiaromatic C) Non-aromatic D) Semi-aromatic 1. Select an antiaromatic Annulenes/Ions having 4 pi electrons system present in the molecule 2. Select an antiaromatic Annulenes/Ions having 8 pi electrons system present in the molecule 3. Select an aromatic heterocyclic Annulenes/Ions having 10 pi electrons system present in the molecule The followings are example only Why can't people and animals synthesize the benzene nucleus, a crucial component of phenylalanine? A) Lack of enzymes B) Genetic mutation C) Insufficient energy D) Structural limitation How do people and animals acquire phenylalanine, an essential amino acid? A) Synthesize it from glucose B) Obtain it from sunlight C) Extract it from water D) Acquire it through diet Who can synthesize the aromatic ring and produce their own phenylalanine? A) Humans B) Animals C) Plants and bacteria D) Fungi What is the significance of plants and bacteria being able to synthesize the aromatic ring and phenylalanine? A) They have specialized enzymes B) They lack dietary requirements C) They can survive in harsh environments D) They contribute to the food chain Which of the following organisms can produce phenylalanine without dietary intake? A) Humans B) Animals C) Plants D) Bacteria What is the key structural feature of pyrrole that contributes to its aromaticity? A) Six-membered ring B) Nitrogen atom C) Three double bonds D) Lone pair of electrons on nitrogen How many pi electrons does pyrrole appear to have initially? A) 2 B) 4 C) 6 D) 8 What role does the lone pair of electrons on the nitrogen atom play in pyrrole's aromaticity? A) It disrupts the aromaticity B) It occupies a non-p orbital C) It participates in the pi bonding system D) It forms a new double bond How many electrons from the nitrogen atom contribute to the pi bonding system in pyrrole? A) None B) One C) Two D) Three How many pi electrons are involved in the aromatic sextet of pyrrole? A) 4 B) 6 C) 8 D) 10 What is the key structural feature of pyrimidine that distinguishes it from other heterocycles? A) Five-membered ring B) Three nitrogen atoms C) Two nitrogen atoms in a 1,3- arrangement D) Four nitrogen atoms How are the lone pairs of electrons on the nitrogen atoms in pyrimidine oriented? A) Perpendicular to the ring B) In a non-p orbital C) In the plane of the aromatic ring D) Forming new double bonds What is the role of the lone pairs of electrons on the nitrogen atoms in pyrimidine's aromaticity? A) They contribute to the aromatic sextet B) They disrupt the aromaticity C) They are not involved in the aromatic system D) They form a new pi bond How many nitrogen atoms are present in pyrimidine? A) One B) Two C) Three D) Four How do the lone pairs of electrons on the nitrogen atoms in pyrimidine compare to those in pyridine? A) They are not basic B) They are not in the plane of the ring C) They are involved in the aromatic system D) They are basic and not part of the aromatic sextet What is the key structural feature of imidazole that contributes to its aromaticity? A) Three nitrogen atoms B) Two oxygen atoms C) Two nitrogen atoms D) Four nitrogen atoms How many nitrogen atoms are present in imidazole? A) One B) Two C) Three D) Four What is the role of the lone pair of electrons on one of the nitrogen atoms (bonded to hydrogen) in imidazole's aromaticity? A) It disrupts the aromatic system B) It is part of the aromatic sextet C) It forms a new double bond D) It is not involved in the aromatic system Which nitrogen atom in imidazole has its lone pair participating in the aromatic sextet? A) The nitrogen bonded to hydrogen B) The nitrogen not bonded to hydrogen C) Both nitrogen atoms D) Neither nitrogen atom How is the lone pair of electrons on the nitrogen atom not bonded to hydrogen in imidazole described? A) Aromatic B) Non-basic C) Involved in the aromatic system D) Basic and not part of the aromatic sextet What distinguishes furan from other aromatic heterocycles like pyrrole and imidazole? A) Presence of a six-membered ring B) Oxygen as the heteroatom C) Three nitrogen atoms D) Lack of lone pairs on the heteroatom How many lone pairs of electrons does the oxygen atom in furan typically have? A) None B) One C) Two D) Three How is the oxygen atom in furan hybridized? A) sp hybridization B) sp3 hybridization C) sp2 hybridization D) dsp3 hybridization How do the electrons from the lone pair on the oxygen atom in furan contribute to its aromatic sextet? A) They disrupt the aromaticity B) They form new bonds C) They combine with the double bond electrons to complete the sextet D) They are not involved in the aromatic system How does thiophene differ structurally from furan? A) Presence of a six-membered ring B) Oxygen as the heteroatom C) Sulfur in place of oxygen D) Lack of aromaticity What atom replaces the oxygen in thiophene? A) Nitrogen B) Carbon C) Sulfur D) Hydrogen How does the use of the unhybridized 3p orbital by the sulfur atom affect the bonding in thiophene compared to furan? A) Increases aromaticity B) Decreases aromaticity C) Enhances stability D) Reduces stability What defines polynuclear aromatic hydrocarbons? A) Single benzene rings B) Fused benzene rings C) Non-aromatic structures D) Linear hydrocarbon chains Which compound is considered the simplest fused (two ring) aromatic compound? A) Anthracene B) Phenanthrene C) Naphthalene D) Benzene How does the reactivity of compounds like anthracene and phenanthrene change as the number of fused aromatic rings increases? A) Becomes less reactive B) Becomes more reactive C) Remains unchanged D) Reactivity is unpredictable What characteristic distinguishes polynuclear aromatic hydrocarbons from benzene in terms of stability? A) Higher stability B) Lower stability C) Equal stability D) Variable stability How do anthracene and phenanthrene differ in their reactivity compared to benzene? A) Less reactive B) More reactive C) Equally reactive D) Unpredictable reactivity How does the reactivity of larger polynuclear aromatic hydrocarbons compare to anthracene and phenanthrene? A) Less reactive B) More reactive C) Equally reactive D) Unpredictable reactivity Example: MCQ based on the provided molecule structure 1. Select a Kekule’s structure of Phenanthrene 2. Identify a drug contained fused-ring heterocycles- indole 3. Identify Styrene a benzene derivatives 4. Identify anisole a benzene derivatives 5. Identify benzaldehyde a benzene derivatives 6. Identify benzenesulfonic acid- a benzene derivatives What is the primary economic significance of sulfonation in the chemical industry? A) Production of pharmaceuticals B) Manufacture of dyes and pigments C) Synthesis of polymers and plastics D) Production of detergents What is the product of the sulfonation of an alkylbenzene? A) Alkylbenzene sulfate B) Alkylbenzene sulfonate C) Alkylbenzene sulfonic acid D) Alkylbenzene sulfite What is the role of the base in the neutralization process after the sulfonation of an alkylbenzene? A) To increase the reactivity of the sulfonic acid B) To remove excess sulfuric acid C) To neutralize the sulfonic acid to form a salt D) To initiate the sulfonation reaction What is the resulting product after neutralizing the alkylbenzenesulfonic acid with a base? A) Alkylbenzene sulfate B) Alkylbenzene sulfonate C) Alkylbenzene sulfonic acid D) Alkylbenzene sulfite What is the term for the increased reactivity of toluene compared to benzene in electrophilic aromatic substitution reactions? A) Deactivation B) Activation C) Substitution D) Directing What is the primary product of the nitration of toluene? A) Meta-substituted product B) Ortho-substituted product C) Para-substituted product D) Mixture of ortho and para-substituted products Which of the following catalysts is commonly used in the Friedel–Crafts alkylation reaction? A) Aluminum sulfate B) Aluminum chloride C) Aluminum oxide D) Aluminum nitrate Which of the following is the name of the reaction between alkyl halides and benzene in the presence of Lewis acid catalysts? A) Friedel–Crafts acylation B) Friedel–Crafts alkylation C) Friedel–Crafts sulfonation D) Friedel–Crafts nitration What is the role of the Lewis acid catalyst in the Friedel–Crafts alkylation reaction? A) To increase the reactivity of the alkyl halide B) To remove excess hydrogen chloride C) To initiate the reaction D) To neutralize the alkyl halide Example of reaction: Chemical reaction will be provided 1. Name the following chemical reaction- Friedel-Crafts Alkylation 2. Identify the chemical reaction for Clemmensen reduction 3. Identify the chemical reaction for Friedel-Crafts acylation 4. Identify the chemical reaction for Friedel-Crafts alkylation 5. Differentiate the term acylation and alkylation 6. Identify the alpha-carbon in the following alkylbenzene structure 7. Identify Oxidation reaction of Phenol to quinone Identify …………….Chemical reaction of (chemical reaction will be provided) Oxidation reaction Reduction reaction Substitution reaction Addition reaction Find a chemical reaction where phenol is acylated to give esters The following is the chlorobenzene. Nitration of chlorobenbenze (below structure) is Only Meta position Only Ortho position Only Para position Both ortho and para position Directing effects on substituent on benzene: Identify meta-directing functional group Identify ortho, para directing functional groups A. -OH B. -NH2 C. -NO2 D. C=O E. -X F. -OCH3 G. -CH3 Identify a chemical reaction from the following is an example of neutralization reaction Identify which chemical reaction is named sulfonation Example of local anesthetics A. Benzocine B. Procaine C. Nitrophenol D. Aniline Nitration of benzene A. Oxidation reaction B. Reduction reaction Find out in tobacco smoke which compound is present Short answer practice:  Nomenclature of benzene derivatives/Naming  Hückel’s rule and aromaticity  Explain how several Heterocyclic compounds are aromatic  Structure of benzene