Rusting of an article made up of iron is called

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

$A$ mixture of sulphur and carbon disulphide is

Differentiate between an element and a compound. Categorize the following substances into elements and compounds: Sodium chloride,Iodine,Water,$24$ carat gold,Oxygen gas,Carbon.

$(i)$ Name a technique to separate a mixture of two or more miscible liquids for which the difference in boiling points is less than $25\, K$.
$(ii)$ Describe the structure of the column used in the above technique. Why is it used?

Based on which factor is a solution said to be dilute,concentrated,or saturated?