Which of the following is TRUE?
a. Toluene is polar and is miscible with glycerol.
b. Toluene is nonpolar and is miscible with glycerol.
c. Naphthalene is polar and is soluble in water.
d. Naphthalene is nonpolar and is soluble in toluen
The correct answer and explanation is:
The correct answer is d. Naphthalene is nonpolar and is soluble in toluene.
Explanation:
Toluene and naphthalene are both nonpolar compounds. Toluene (C₆H₅CH₃) is a simple aromatic hydrocarbon, and naphthalene (C₁₀H₈) is a polycyclic aromatic hydrocarbon. In general, nonpolar substances tend to be soluble in other nonpolar solvents due to the principle of “like dissolves like.” This means that nonpolar substances, such as naphthalene and toluene, will mix together or dissolve in each other. The intermolecular forces between nonpolar molecules primarily involve dispersion forces (also known as London forces), which are weak attractive forces between molecules due to temporary dipoles.
In the case of naphthalene and toluene, the dispersion forces are sufficiently similar, allowing naphthalene to dissolve in toluene. The solubility of naphthalene in toluene is not an isolated case; it is common for nonpolar substances to dissolve in other nonpolar solvents.
Looking at the other options:
- a. Toluene is polar and is miscible with glycerol: This statement is false because toluene is nonpolar, and glycerol (C₃H₈O₃) is a polar compound. Nonpolar substances typically do not mix well with polar solvents due to the lack of favorable intermolecular interactions.
- b. Toluene is nonpolar and is miscible with glycerol: This statement is also false. While toluene is nonpolar, glycerol is polar, and nonpolar substances are generally immiscible with polar substances. Hence, toluene and glycerol will not form a homogeneous mixture.
- c. Naphthalene is polar and is soluble in water: This is incorrect. Naphthalene is nonpolar, and water is highly polar. Nonpolar substances do not dissolve well in water because there is a lack of interaction between the water molecules and the nonpolar naphthalene molecules.
In conclusion, the correct statement is d. Naphthalene is nonpolar and is soluble in toluene, as both compounds share similar nonpolar characteristics that allow them to dissolve in each other.