In which situation can a mixture always be called a solution?

• A. When the mixture separates upon standing
• B. When the mixture is homogeneous at the molecular level
• C. When the mixture is composed of two immiscible liquids
• D. When the mixture contains visible particles

Answer: (B)

Verified step by step guidance

1. Understand the definition of a solution: a solution is a homogeneous mixture where the solute particles are uniformly distributed at the molecular or ionic level within the solvent.
2. Recognize that a mixture that separates upon standing is not a solution because solutions do not separate over time; they remain uniform.
3. Identify that immiscible liquids form heterogeneous mixtures because they do not mix uniformly at the molecular level, so they are not solutions.
4. Note that visible particles indicate a heterogeneous mixture, as solutions have particles too small to be seen with the naked eye.
5. Conclude that only a mixture that is homogeneous at the molecular level can always be called a solution.