$(a)$ Write any three points of differences between homogeneous and heterogeneous mixtures.
$(b)$ Give two reasons for supporting that water is a compound and not a mixture.

(N/A) Differences between homogeneous and heterogeneous mixtures:

Homogeneous mixture	Heterogeneous mixture
$(i)$ Composition is uniform throughout.	$(i)$ Composition is not uniform throughout.
$(ii)$ No visible boundaries of separation.	$(ii)$ Distinct boundaries of separation are visible.
$(iii)$ Components are not easily separated (e.g.,sugar in water).	$(iii)$ Components can be easily separated (e.g.,oil and water).

$(b)$ Reasons to support that water is a compound and not a mixture:
$(i)$ Water has a fixed chemical composition $(H_2O)$ and its components can be separated only by chemical methods like electrolysis,not by physical means.
$(ii)$ The properties of water are entirely different from the properties of its constituent elements,hydrogen (a combustible gas) and oxygen (a supporter of combustion).