Question

Classify the following as homogeneous heterogeneous mixture:

i) sodium chloride water ii) sand water

iii) glucose water iv) iron filings and water

Answer 1

In homogeneous mixture, the components intermingle and the resultant solution has uniform constitution and particles of the components cannot be seen with naked or nor do they scatter a beam of light. In a heterogeneous mixture, the particles of solid are suspended throughout the liquid and these mixtures are capable of scattering a beam of visible light.
In certain type of heterogeneous mixture like a suspension, the particles of solute are visible to the naked eye while in other heterogeneous systems like colloids, particles of solute cannot be seen by the naked eye.

Sodium chloride in water and glucose in water: homogeneous mixture

On dissolving sodium chloride/glucose in water, crystals of sodium chloride/glucose disappear and the resultant solution is salty/sweet. The salt/glucose is uniformly distributed in water.

Sand water and iron filings and water are heterogeneous mixtures.

Sand and iron filings do not uniformly dissolve after mixing. With time, they separate and settle down and particles of these are visible to the naked eye.