Practice Questions

Recall the order of reactivity of primary, secondary, and tertiary alcohols with a given haloacid, such as $HCl$.

Name the reaction that describes the treatment of an alkyl halide with sodium metal in dry ether to form an alkane with double the number of carbon atoms.

Define a haloalkane and a haloarene, specifying the hybridization of the carbon atom to which the halogen is attached in each case.

Design a single-step synthesis for 1-fluorobutane starting from 1-chlorobutane. Name the specific reaction and justify your choice of reagent.

Compare the boiling points of n-butyl bromide and tert-butyl bromide and provide a reason for the difference.

Justify why the synthesis of a Grignard reagent ($RMgX$) must be conducted under strictly anhydrous conditions.

Define the term 'ambident nucleophile' and provide one example.

Solve for the major organic product of the Fittig reaction when chlorobenzene is treated with sodium metal in dry ether.

Apply IUPAC nomenclature rules to name the compound with the following structure: $CH_3CH(Br)CH_2C(CH_3)_2Cl$.

Name the specific halogen exchange reaction used for the preparation of alkyl iodides.

Create a justification for why the C-Cl bond length in chlorobenzene (169 pm) is shorter than in chloroethane (178 pm).

Name the poisonous gas that can be formed from chloroform ($CHCl_3$) upon exposure to light and air.

Explain why para-isomers of dihalobenzenes have higher melting points compared to their ortho- and meta-isomers.

Summarize the key differences between $S_N1$ and $S_N2$ reactions with respect to their kinetics, number of steps, and stereochemical outcome.

Identify the following as allylic or vinylic halides: (i) $CH_3CH=CHCH_2Br$ (ii) $CH_2=CHBr$.

Explain the effect of branching on the boiling points of isomeric haloalkanes.

Describe the classification of dihaloalkanes as geminal and vicinal dihalides, providing one structural example for each.

Describe the Sandmeyer's reaction for the preparation of chlorobenzene, including the necessary chemical equations.

Demonstrate how you would prepare 1-iodobutane from but-1-ene. Provide the necessary reagents and reaction equations.

Compare the dipole moments of ortho-, meta-, and para-dichlorobenzene. Analyze the reason for the observed trend.

Demonstrate a two-step synthesis to convert toluene ($C_6H_5CH_3$) to benzyl alcohol ($C_6H_5CH_2OH$) using a haloalkane intermediate. Specify all reagents and conditions.

Analyze why Grignard reagents ($RMgX$) must be prepared and used under anhydrous (dry) conditions. Demonstrate with a chemical equation.

Examine the role of anhydrous $AlCl_3$ in the Friedel-Crafts alkylation of chlorobenzene with methyl chloride ($CH_3Cl$).

Propose a chemical test to distinguish between chlorobenzene and benzyl chloride. Justify your proposal with expected observations and reactions.

When 2-bromopentane is treated with an alcoholic solution of potassium hydroxide, formulate all possible alkene products. Justify which alkene will be the major product by citing the relevant rule and explaining its underlying principle.

Design an experimental method to separate a mixture of ortho-dichlorobenzene and para-dichlorobenzene. Justify your choice of method by evaluating their relevant physical properties.

Critique the assertion that the reaction between tert-butyl bromide and aqueous KOH is second-order because two reactants are present. Provide the correct kinetic order and justify your reasoning with the reaction mechanism.

Evaluate the use of Freons and DDT, justifying why their applications have been severely restricted despite their initial benefits.

Propose a multi-step synthesis pathway to convert aniline ($C_6H_5NH_2$) into iodobenzene ($C_6H_5I$). Name the key reaction involved.

Explain why the reaction of an alcohol with thionyl chloride ($SOCl_2$) is considered a preferred method for preparing an alkyl chloride.

Compare the reactivity of chlorobenzene and cyclohexyl chloride towards nucleophilic substitution reactions. Analyze the reasons for the difference.

A primary alkyl halide, 1-bromobutane ($C_4H_9Br$), is treated separately with alcoholic KOH and aqueous KOH. Analyze the reaction in each case, identify the major product formed, and explain the underlying mechanism.

Solve for the major alkene product formed when 2-bromopentane is heated with an alcoholic solution of potassium hydroxide. Justify your answer using Zaitsev's rule.

Apply the concept of leaving group ability to determine which compound would react faster in an $S_N2$ reaction: 1-chloropropane or 1-iodopropane. Explain your choice.

A student proposes using concentrated $H_2SO_4$ during the reaction of an alcohol with KI to prepare an alkyl iodide. Justify why this is a flawed method and propose a more suitable reagent.

Critique the statement: 'All chiral molecules possess a chiral center.'

Examine the stereochemical outcome when optically active 2-bromopentane undergoes a substitution reaction with $OH^-$ via (a) $S_N1$ mechanism and (b) $S_N2$ mechanism.

Analyze the competition between substitution ($S_N$) and elimination (E) reactions for a secondary alkyl halide like 2-bromopropane. Discuss how the nature of the nucleophile/base and temperature can be used to favor one reaction over the other.

Design a two-step synthesis route to convert propene ($CH_3CH=CH_2$) to 1-bromopropane. Justify the choice of reagents and conditions for each step, explaining how you would avoid the formation of the major Markovnikov product.

Summarize the preparation of haloalkanes from alcohols using three different types of reagents and write one general chemical equation for each method.

Evaluate the statement: 'The $S_N1$ reaction of an optically active alkyl halide always results in a racemic mixture.' Propose a reason why complete racemisation might not be observed in reality.

Contrast the major products formed when bromoethane ($CH_3CH_2Br$) reacts with potassium cyanide (KCN) and silver cyanide (AgCN). Explain the reason for this difference.

List the four main reasons that explain why haloarenes are less reactive than haloalkanes towards nucleophilic substitution reactions.

Evaluate and compare the reactivity of vinyl chloride ($CH_2=CHCl$) and allyl chloride ($CH_2=CHCH_2Cl$) towards nucleophilic substitution reactions. Justify your comparison by considering intermediate stability and carbon hybridization.

Formulate a mechanism to explain why an electron-withdrawing group ($-\text{NO}_2$) at the para-position greatly enhances the reactivity of chlorobenzene towards nucleophilic aromatic substitution, while the same group at the meta-position has a negligible effect. Use resonance structures to support your argument.