Cyclohexene (boiling point = 83 °C) can be prepared by the dehydration of cyclohexanol (boiling point = 161 °C) using concentrated phosphoric acid - AQA - A-Level Chemistry - Question 3 - 2018 - Paper 3

Sodium carbonate solution was used to wash the distillate to neutralize any acids present and to remove any water-soluble impurities, preventing contamination of the product and increasing its purity.

It is important to open the tap of the separating funnel periodically to release any pressure build-up caused by gases and to allow for proper phase separation, preventing any accidents or overflow.

Anhydrous calcium chloride is hygroscopic, meaning it has a strong affinity for moisture and can absorb excess water effectively, ensuring that the organic product remains dry.

The apparatus consists of a Buchner funnel, a filter paper placed inside the funnel, and a vacuum source connected to the funnel. The mixture containing the drying agent is poured into the funnel, and when the vacuum is activated, the liquid is drawn through the filter paper, leaving the drying agent behind.

Cyclohexene has a shorter retention time than cyclohexanol because it is less polar and has lower affinity for the stationary phase (silica gel) in column chromatography, allowing it to elute faster compared to the more polar cyclohexanol.

An infrared spectrum would show the absence of the characteristic -OH stretching peak around 3200-3600 cm⁻¹, which is specific to alcohols like cyclohexanol. The presence of signals corresponding to the alkene (C=C) double bond would confirm that cyclohexene is present while indicating no cyclohexanol is present.