Which of the following is true about suspensions?

• A. They are always completely uniform
• B. They are immiscible and tend to separate when standing
• C. They always dissolve in water
• D. They are always solids

Answer: (B)

Suspensions are mixtures where solid particles are dispersed in a liquid but not dissolved. Because these particles are larger and heavier than the liquid’s molecules, they don’t stay evenly mixed and will settle out under gravity if the mixture is left standing. That settling leads to separation into a clearer liquid layer and a sediment, which is why suspensions are described as immiscible and tending to separate over time.

This also explains why the other statements aren’t correct: suspensions aren’t perfectly uniform—you can often see or feel the difference between the settled particles and the liquid. They don’t have to dissolve in water—the dispersed particles remain solid and separate rather than dissolving. And while many suspensions involve solids in liquids, the key idea is the lack of dissolution and the tendency to settle, not that the dispersed phase must always be solid in all possible cases.