Tert-Butyl methyl ether has a density of 0.74 g/mL.
a. tert-butyl methyl ether
b. H2O
c. The order is temperature dependent.
d. These solvents are miscible; there are no layers
The Correct Answer and Explanation is :
Correct Answer: b. H₂O
Explanation:
In a liquid-liquid extraction or when two immiscible liquids are mixed, the relative densities of the liquids determine which layer will settle on the bottom and which will float on top. The denser liquid will form the bottom layer, while the less dense liquid will form the top layer.
Let’s compare the densities of tert-butyl methyl ether (TBME) and water (H₂O):
- Density of tert-butyl methyl ether = 0.74 g/mL
- Density of water = 1.00 g/mL (at room temperature)
Because 0.74 g/mL is less than 1.00 g/mL, TBME is less dense than water. Therefore, TBME will float on top, and water will form the bottom layer.
This principle is commonly used in laboratory procedures such as liquid-liquid extraction, where it is critical to identify the aqueous (usually water-based) and organic (solvent-based) layers. Since TBME is an organic solvent and water is polar, they are immiscible—meaning they do not mix and will separate into distinct layers. This rules out option d, which suggests miscibility.
Why other options are incorrect:
- a. tert-butyl methyl ether: Incorrect. TBME has a lower density than water and thus will be the top layer, not the bottom.
- c. The order is temperature dependent: Incorrect. Although density can slightly change with temperature, the difference in density between TBME and water is significant enough that normal laboratory temperature variations will not reverse their order.
- d. These solvents are miscible; there are no layers: Incorrect. TBME and water are immiscible, so they will form two layers.
Conclusion:
Since water is denser, it will form the bottom layer, and TBME will float on top. Understanding the densities of solvents is essential in laboratory separations and extractions.
Correct answer: b. H₂