Post-Lab Multiple Choice Questions

Toluene is a known aromatic compound. If you observed no change in the color of the bromine solution in test tube F (containing toluene) after 15 minutes, what can you conclude?

• Toluene has a higher boiling point than cyclohexane and cyclohexene, affecting the reaction rate.

• Aromatic compounds like toluene are more reactive towards bromine than alkenes under these conditions.

• The black sugar paper used on test tube A prevented the reaction from occurring.

• Toluene, unlike alkenes, does not undergo an addition reaction with bromine at room temperature.

You observed a complete disappearance of the reddish brown color of bromine solution in test tube D after 15 minutes. Which of the following is the MOST LIKELY explanation?

• The reaction between bromine and cyclohexene (in test tube D) is endothermic and requires light for the reaction to proceed.

• Bromine reacts readily with all hydrocarbons under these conditions.

• Cyclohexene (in test tube D) is an alkane and does not react with bromine.

• Cyclohexene (in test tube D) is an alkene and readily undergoes an addition reaction with bromine, causing the disappearance of the reddish brown color.

Test tube B was kept in sunlight along with cyclohexene. If you observed a persistence of the reddish brown color of bromine solution in test tube B after 15 minutes, compared to test tube D, what can you determine?

• Light accelerates the reaction between bromine and cyclohexene.

• Sunlight decomposes cyclohexene, preventing its reaction with bromine.

• The absence of light hinders the reaction between bromine and cyclohexene.

• Dichloromethane is not an effective solvent for this experiment.

Based on this experiment, which property can differentiate between alkanes and alkenes?

• Boiling point

• Density

• Presence of double bonds

• Solubility in water

Which of the following observations would strengthen the conclusion that the disappearance of the reddish brown color is due to a reaction between bromine and the organic compound?

• A white precipitate forms at the bottom of the test tube after 15 minutes.

• The solution in the test tube feels warm compared to others after 15 minutes.

• A gas is produced when the bromine solution is added to the organic compound.

• The reddish brown color disappears more slowly in test tubes kept in the dark compared to those in sunlight.