Use this free practice quiz with 20 questions to review 07 Alkenes and Alkynes, test your knowledge, and prepare for your next test or exam.
A student predicts that adding HBr to propene in the presence of peroxides will predominantly form 1-bromopropane, but does not apply the same peroxide exception to HCl or HI. Is this prediction consistent with standard introductory reaction rules?
True
False
When an alkene reacts with Br2 to form a vicinal dibromide, which pathway and relative stereochemistry best describe the addition?
A carbocation forms and the halogens add syn.
A bridged halonium ion forms and the halogens add anti.
A free radical forms and the halogens add syn.
A bridged halonium ion forms and the halogens add syn.
What alcohol is the main product when 1-butene undergoes hydroboration–oxidation using 1. BH3·THF; 2. H2O2, OH−?
In mercury-catalyzed hydration of an alkyne, the initially formed enol converts to a carbonyl compound by .
What is the characteristic product when an alkyne is partially reduced using sodium in liquid ammonia?
An alkane
A cis alkene
A trans alkene
A geminal dihalide
Select all statements that accurately describe alkene oxidation outcomes.
Ozonolysis followed by a reductive workup cleaves a C=C bond into carbonyl compounds.
OsO4 cleaves a C=C bond into two carboxylic acids.
Hot acidic KMnO4 can oxidize aldehydes formed by cleavage further to carboxylic acids.
Epoxidation with a peroxyacid cleaves the C=C bond into aldehydes.
For a terminal alkyne, one equivalent of HX usually gives a vinyl halide, whereas excess HX can give a geminal dihalide with both halogens on the same carbon. Is this statement correct?
True
False
Strong oxidative cleavage of a terminal alkyne breaks its C≡C bond. Name the two product types formed.
When an alkyne reacts with one equivalent of Br2, the typical product is a .
Which carbonyl compound is the main product when 1-butyne undergoes hydroboration–oxidation with a bulky borane?
2-butanone
Butanal
1-butanol
Butanoic acid
A chemist wants to hydrate an unsymmetrical alkene with Markovnikov regiochemistry while avoiding rearrangements associated with a free carbocation. Which method best fits this goal?
Oxymercuration–demercuration: 1. Hg(OAc)2, H2O; 2. NaBH4
Hydroboration–oxidation: 1. BH3·THF; 2. H2O2, OH−
Acid-catalyzed hydration: H2O, H+
Catalytic hydrogenation: H2 with a metal catalyst
Select all accurate predictions for hydrogenation or partial reduction of carbon–carbon multiple bonds.
An alkyne reduced with Lindlar catalyst gives a cis alkene.
An alkyne reduced with sodium in liquid ammonia gives a trans alkene.
An alkyne treated with excess H2 and an active metal catalyst is usually reduced to an alkane.
An alkene treated with H2 and a metal catalyst gives a trans alkene by anti addition.
Compare the reaction of an unsymmetrical alkene with Br2 alone and with Br2 in water. For each reaction, describe the intermediate, the attacking nucleophile, the regiochemical outcome where relevant, and the relative stereochemistry.
An alkene is treated with a peroxyacid such as RCO3H. What type of product forms directly from the C=C bond?
A vicinal dihalide
A 1,2-diol
An epoxide
A carboxylic acid
What product class is typically formed when excess HX adds to a terminal alkyne?
A vicinal dihalide with one halogen on each carbon
A geminal dihalide with both halogens on one carbon
A dihaloalkene with the halogens on different carbons
A carboxylic acid
True or false: Because a carbocation intermediate is planar, typical electrophilic addition of HX to an alkene is generally not stereospecific.
True
False
What is the predominant organic product when propene reacts with HBr in the presence of peroxides?
2-bromopropane
1-bromopropane
1,2-dibromopropane
propan-2-ol
Propene reacts with Br₂ in water to form a halohydrin. Which description best fits the major product?
OH attaches to the terminal carbon, and Br and OH add syn
Br attaches to the middle carbon, and Br and OH add syn
OH attaches to the middle carbon, and Br and OH add anti
OH attaches to the middle carbon, and Br and OH add without a specified relationship
What alcohol is formed when 1-butene undergoes hydroboration–oxidation using BH₃·THF, followed by H₂O₂ and OH⁻? Enter the product's IUPAC name.
What is the final carbonyl product when 1-butyne is hydrated with H₂SO₄, H₂O, and HgSO₄? Enter the product's IUPAC name.