Which of the following is an example of a heterogeneous solution? 

The correct answer is Mixture of oil in water.

Key Points

• A heterogeneous solution is one where the components are not uniformly distributed, and different phases are visible.
• In a mixture of oil and water, the two liquids do not mix uniformly and form separate layers, making it a classic example of a heterogeneous mixture.
• The oil floats on water due to its lower density, creating a distinct interface between the two liquids.
• This type of mixture can be easily separated by physical means such as decantation or using a separating funnel.

Additional Information

• Homogeneous Mixture
  • A homogeneous mixture has a uniform composition throughout, and its components are not visibly distinguishable.
  • Examples include solutions like salt water and air, where the solute and solvent are uniformly distributed.
• Suspensions
  • A suspension is a type of heterogeneous mixture where solid particles are dispersed in a liquid or gas but are not dissolved.
  • Over time, these particles may settle out of the mixture due to gravity.
  • An example of a suspension is muddy water.
• Colloids
  • Colloids are mixtures where very small particles of one substance are evenly distributed throughout another substance.
  • Unlike suspensions, colloidal particles do not settle out over time.
  • Examples include milk, gelatin, and fog.
• Emulsions
  • An emulsion is a type of colloid consisting of two immiscible liquids, where one liquid is dispersed in the other.
  • Common examples include mayonnaise and lotions.
  • Emulsifying agents are often used to stabilize emulsions and prevent the liquids from separating.