Calculate the mass of sodium sulphate required to prepare its $20\%$ (mass percent) solution in $100\,g$ of water. (in $,g$)

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

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.

Tincture of iodine has antiseptic properties. This solution is made by dissolving

Which of the two will scatter light: soap solution or salt solution?

How much water should be added to $15 \, g$ of salt to obtain a $15 \%$ salt solution (in $, g$)?