Hydrocarbons: alkanes and alkenes (AS)：練習題

Which condition is essential for the reaction between methane and chlorine to form chloromethane?

An alkene undergoes complete oxidative cleavage when heated under reflux with concentrated acidified \(\text{KMnO}_4\).
The only organic products formed are ethanoic acid, \(\text{CH}_3\text{COOH}\), and propanoic acid, \(\text{CH}_3\text{CH}_2\text{COOH}\).
What is the structure of the original alkene?

A hydrocarbon, \(\text{X}\), contains \(85.7\%\) carbon by mass and has a relative molecular mass of \(84\).
Compound \(\text{X}\) reacts with cold, dilute acidified \(\text{KMnO}_4\) to form a diol with two chiral centres.
Oxidation of \(\text{X}\) with hot, concentrated acidified \(\text{KMnO}_4\) yields a single carboxylic acid with no other organic product.
What is the IUPAC name of compound \(\text{X}\)?

Alkanes are generally unreactive towards polar reagents. Which statement best explains this observation?

In the free-radical bromination of ethane, which equation represents a termination step?

State the type of hybridisation shown by the two carbon atoms involved in the double bond of an ethene molecule, \(C_{2}H_{4}\).

Explain the origin of geometrical isomerism in but-2-ene with reference to the type of bonding present between the carbon atoms.

An unbranched alkene, \(X\), with molecular formula \(C_{6}H_{12}\), exhibits cis-trans isomerism and yields a single organic product, propanoic acid, when heated under reflux with concentrated acidified potassium manganate(VII), \(KMnO_{4}\).
Deduce the systematic IUPAC name of alkene \(X\).

Ethene, \(C_2H_4\), is an unsaturated hydrocarbon that undergoes addition reactions.

(a) State the reagents and essential conditions required to convert ethene into ethane. [2]

(b) Ethene reacts with cold, dilute, acidified potassium manganate(VII), \(KMnO_4\).
(i) State the colour change observed during this reaction. [1]
(ii) Give the systematic IUPAC name of the organic product formed. [1]

2-Methylbut-2-ene reacts with hydrogen bromide, \(HBr\), to form two isomeric bromoalkanes, one of which is the major product.

(a) State the type and mechanism of this reaction. [1]

(b) Draw the structural formula and state the systematic IUPAC name of the major product. [2]

(c) Explain why this product is formed as the major product rather than the minor product, with reference to the relative stabilities of the carbocation intermediates. [2]