Which of the following is a compound?

Define the term $solution$. Identify the solute and solvent in the following solutions:
$(i)$ Tincture of iodine
$(ii)$ Polluted air
$(iii)$ Soda water
$(iv)$ Dilute hydrochloric acid

Colloids are quite stable. Name the process by which you can separate the components of a colloidal solution.

State the principle involved in separating a mixture containing kerosene and water.

Why is the path of light not visible in a solution when a beam of light is passed through it?

$(a)$ 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.