"Tyndall Effect can be observed when sunlight passes through the canopy of dense forest." Explain how this occurs.

Classify the following as sol,solution,or suspension:
$(i)$ Milk of magnesia
$(ii)$ Coloured gemstones
$(iii)$ Aerated drinks
$(iv)$ Emulsion paint

$(a)$ What separation technique will you apply for the separation of the following?
$(i)$ Ammonium chloride from sodium chloride.
$(ii)$ Different pigments from the extract of flower petals.
$(b)$ What is crystallisation? List two ways in which the crystallisation technique is better than the simple evaporation technique.

$A$ group of students took an old shoe box and covered it with black paper from all sides. They fixed a source of light (a torch) at one end of the box by making a hole in it and made another hole on the other side to view the light. They placed a milk sample contained in a beaker/tumbler in the box as shown in the figure. They were amazed to see that the milk taken in the tumbler was illuminated. They tried the same activity by taking a salt solution but found that light simply passed through it.
$(a)$ Explain why the milk sample was illuminated. Name the phenomenon involved.
$(b)$ Same results were not observed with a salt solution. Explain.
$(c)$ Can you suggest two more solutions which would show the same effect as shown by the milk solution?

Smoke and fog both are aerosols. In what way are they different?

Which of the following is an aqueous solution?