3.3.4.1 Structure/bonding/reactivity

What is the empirical formula of 4-hydroxypent-2-ene?

• C₅H₁₂O

• C₅H₁₀O

• CH₂O

• C₅H₉OH

Z-Retinal, shown in the diagram, is a component in vitamin A.

Which of the double bonds, labelled A, B, C or D, is responsible for the letter Z in the name?

• A

• B

• C

• D

Which statement about E-1,2-dichloroethene is correct?

• It has the same boiling point as Z-1,2-dichloroethene.

• It forms a polymer with the same repeating unit as Z-1,2-dichloroethene.

• It has the same IR spectrum as Z-1,2-dichloroethene in the range 400–1500 cm⁻¹.

• It has a molecular ion peak different from that of Z-1,2-dichloroethene in its mass spectrum.

Which statement about ethene is correct?

• It has no geometric isomers because there is free rotation around the C=C bond.

• It reacts with HBr in a nucleophilic addition reaction.

• It burns in excess oxygen to produce carbon dioxide and water.

• The C=C bond is twice as strong as the C–C bond in ethane.

The correct systematic name for the compound in the image is

• 2-ethyl-3,4-dimethylpent-2-ene

• 4-ethyl-2,3-dimethylpent-3-ene

• 2,3,4-trirnethylhex-3-ene

• 3,4,5-trimethylhex-3-ene