Question

Which of the following volatile oils are heavier than water:

• A. Cumin
• B. Cinnamon
• C. Fennel
• D. Lemongrass

Hint:

Volatile oils with a higher density than water tend to have a strong aroma and are commonly used in aromatherapy and traditional medicine for their therapeutic properties.

Answer 1

The Correct Option is B

Among the listed volatile oils, Cinnamon oil is heavier than water. This is due to its higher density, which is greater than 1 g/cm³, making it denser than water. The other oils listed, such as cumin, fennel, and lemongrass, are generally lighter than water.

Answer 2

The question asks which volatile oil sinks in water rather than floats, that is, which one has a specific gravity above 1. Let's weigh each option.

1. Cumin: Cumin oil is a lighter volatile oil with a specific gravity below 1, so a layer of cumin oil placed on water floats on top, it does not sink.
2. Cinnamon: Cinnamon bark oil is rich in cinnamaldehyde and has a specific gravity greater than 1 (typically around 1.03 to 1.05), which places it in the small group of volatile oils, along with clove and cassia oil, that are actually denser than water. A sample of cinnamon oil added to water settles at the bottom instead of floating.
3. Fennel: Fennel oil, dominated by anethole, has a specific gravity below 1 and floats on water like most common volatile oils.
4. Lemongrass: Lemongrass oil, rich in citral, is also lighter than water and floats when the two are mixed and left to separate.

Most volatile oils are lighter than water and form a floating layer, but a few, cinnamon oil among them, are dense enough to sink below the water layer instead.

Therefore, the correct answer is Cinnamon.