During an experiment, students were asked to prepare a $10\%$ (mass/mass) solution of sugar in water. Ramesh dissolved $10\,g$ of sugar in $100\,g$ of water, while Sarika prepared it by dissolving $10\,g$ of sugar in water to make $100\,g$ of the solution.
$(a)$ Are the two solutions of the same concentration?
$(b)$ Compare the mass percentage of the two solutions.

$(a)$ List any three characteristics of a colloid.
$(b)$ Name the two components of a colloid.
$(c)$ Identify colloids from the following mixtures:
Muddy water,sugar in water,ink,blood,soda water,foam.

The teacher instructed three students $A$,$B$ and $C$ respectively to prepare a $50\%$ (mass by volume) solution of sodium hydroxide $(NaOH)$. $A$ dissolved $50\,g$ of $NaOH$ in $100\,mL$ of water,$B$ dissolved $50\,g$ of $NaOH$ in $100\,g$ of water while $C$ dissolved $50\,g$ of $NaOH$ in water to make $100\,mL$ of solution. Which one of them has made the desired solution and why?

$A$ 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?

What volume of ethyl alcohol and water must be mixed together to prepare $250 \, mL$ of $50 \%$ by volume of alcohol in water?

Define a solution. Give an example of $(i)$ gas in liquid solution $(ii)$ gas in gas solution.