Which of the following statements is/are true?
I. The hydrocarbon methane (CH₄) will dissolve completely in acetone (CH₃COCH₃).
II. Ammonia (NH₃) will form a heterogeneous mixture with carbon tetrachloride (CCl₄).
III. Pentane (C₅H₁₂) will form a homogeneous mixture with carbon tetrabromide (CBr₄).
IV. Methanethiol (CH₃SH) is miscible in fluoromethane (CH₃F).

• A. I only
• B. II and III
• C. II, III, IV
• D. III and IV
• E. None of the above

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the concept of solubility and miscibility. Solubility refers to the ability of a substance to dissolve in a solvent, forming a homogeneous solution. Miscibility is a specific type of solubility where two liquids can mix in any proportion without separating.
2. Step 2: Analyze statement I. Methane (CH4) is a nonpolar molecule, while acetone (CH3COCH3) is a polar solvent. Generally, nonpolar substances do not dissolve well in polar solvents due to the 'like dissolves like' principle.
3. Step 3: Analyze statement II. Ammonia (NH3) is a polar molecule, and carbon tetrachloride (CCl4) is nonpolar. Polar and nonpolar substances typically do not mix well, leading to a heterogeneous mixture.
4. Step 4: Analyze statement III. Pentane (C5H12) and carbon tetrabromide (CBr4) are both nonpolar molecules. Nonpolar substances tend to mix well with each other, forming a homogeneous mixture.
5. Step 5: Analyze statement IV. Methanethiol (CH3SH) and fluoromethane (CH3F) are both polar molecules. Polar substances are generally miscible with each other, meaning they can mix in all proportions.