Hydrocarbons: alkanes and alkenes (AS): Practice Questions

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]