AS Level Haloalkane

Butanedioic acid occurs in amber, algae, lichens, sugar cane and beets. It may be synthesised in two steps from 1,2-dibromoethane. Which reagents could be used for this synthesis?

• step 1: HCN(g),

  step 2: HCl(aq)

• step 1: HCO2Na(aq),

  step 2: HCl(aq)

• step 1: KCN(aq/alcoholic),

  step 2: H2SO4(aq)

• step 1: NaOH(aq),

  step 2: K2Cr2O7/H2SO4(aq)

Which haloalkane will undergo an S_N1 reaction and produce a yellow precipitate when AgNO₃(aq) is added to it?

• 1-chlorobutane

• 1-iodobutane

• 2-chloro-2-methylpropane

• 2-iodo-2-methylpropane

Which reaction will give 2-chloropropane in the best yield?

• Propane gas with chlorine gas in the presence of ultraviolet light

• propan-2-ol with dilute NaCl (aq)

• propan-2-ol with SOCl₂

• propane with dilute HCl (aq)

1,1-dichloropropane reacts with aqueous sodium hydroxide in a series of steps to give propanal. Which term describes the first step of this reaction?

• electrophilic addition

• elimination

• nucleophilic substitution

• oxidation

When 1-bromopropane is treated in succession with two reagents, X and Y, it produces propanoic acid. What are reagents X and Y?

• NaOH(aq)

• HCl(aq)

• KCN in ethanol

• CO₂

• H+/Cr2O7^2-(aq)

When phenacyl chloride, C₆H₅COCH₂Cl, is reacted with aqueous NaOH, the substitution reaction follows an S_N2 mechanism. Which structure represents a species formed during the reaction?

• 
• 
• 
• 

What is the name of compound X?

• 1,1-dibromo-2-propylcyclopentane

• 1,2-dibromo-2-propylcyclopentane

• 1,4-dibromooctane

• 1,5-dibromooctane

Bromine reacts with ethene to form 1,2-dibromoethane. What is the correct description of the organic intermediate in this reaction?

• It has a negative charge

• It is a free radical

• It is a nucleophile

• It is an electrophile

Chloroethane can be used to make sodium propanoate. The intermediate, Q, is hydrolysed with boiling aqueous sodium hydroxide, to give sodium propanoate. Which reagent would produce the intermediate, Q, from chloroethane?

• concentrated ammonia solution

• dilute sulfuric acid

• hydrogen cyanide

• potassium cyanide

Aqueous sodium hydroxide reacts with 1-bromopropane to give propan-1-ol. How should the first step in the mechanism be described?

• by a curly arrow from a lone pair on the OH- ion to the C^δ+ atom of 1-bromopropane

• by a curly arrow from the C^δ+ atom of 1-bromopropane to the OH^- ion

• by a curly arrow from the C–Br bond to the C atom

• by the homolytic fission of the C–Br bond