STPM CHEMISTRY HYDROCARBON REVISION

Organic compound P consists of carbon, hydrogen and oxygen. The percentages of carbon, hydrogen and oxygen by mass in compound P are 54.55%, 9.09% and 36.36% respectively. What is the empirical formula of P? [RMM: H=1.0, C=12.0, O=16.0]

• C₂H₄O

• C₄H₉O

• CH₂O₂

• C₅H₉O₂

Which of the following compounds has at least one π-bond?

• Ethanol

• Propane

• Methoxy methane, (CH₃)₂O

• Benzene

Why are tertiary carbonium ions more stable than primary carbonium ions?

• Tertiary carbonium carriers three negative charges

• Tertiary carbonium carriers three positive charges

• Tertiary carbonium possess three electron donating groups

• Tertiary carbonium is trigonal planar in structure

How many possible isomers are there for an organic compound with the molecular formula of C₄H₁₀O?

• 2

• 3

• 4

• 5

Ethane, CH₃CH₃ and methanol, CH₃OH are two organic compounds. Ethane is insoluble in water but methanol dissolves easily in water. Which of the following statements best explains the difference mentioned?

• Methanol forms intermolecular hydrogen bonds but ethane cannot.

• Methanol has a higher relative molecular mass than ethane.

• Methanol molecule is more polarised than ethane molecule.

• Methanol can form hydrogen bonds with water molecules but ethane cannot.

Which of the following best explains the function of H⁺ ion as an electrophile?

• It is acidic

• It is positively charged

• It can accept electron pair

• It is highly electropositive

Which molecule has carbon atoms with sp³ hybrid opitals?

• CHΞCH

• CH₃CH₃

• CH₂=CH₂

• C₆H₆

Which of the organic compounds below produces the least amount of carbon dioxide when one mole of the respective compound is combusted in air?

• Propene

• Ethane

• Pentene

• Butane

Propene is reacted with hydrogen chloride and the product is 1-chloropropane. Which of the following statements is true?

• 1-chloropropane is the only possible product that can be collected

• This is an example of nucleophilic addition reaction

• Benzoyl peroxide is added when the reaction occurs

• The product yielded is according to Markovnikov's rule

Which of the following reagents reacts with ethene to give us ethanol?

• Cold acidified potassium manganate (VII)

• Hot acidified potassium manganate (VII)

• Concentrated sulphuric acid, followed by hydrolysis with water

• Oxygen, catalysed with argentum at 200^⋄C. followed by hydrolysis with water