What are the two components of a solution?

Which of the following are chemical changes?
$(i)$ Decaying of wood
$(ii)$ Burning of wood
$(iii)$ Sawing of wood
$(iv)$ Hammering of a nail into a piece of wood

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

Explain why particles of a colloidal solution do not settle down when left undisturbed,while in the case of a suspension they do.

Three students $A, B$ and $C$ prepared mixtures using chalk powder,common salt and milk respectively in water. Whose mixture
$(i)$ would not leave residue on filter paper after filtration?
$(ii)$ would show Tyndall effect?
$(iii)$ would give transparent/clear solution?
$(iv)$ would settle down at the bottom when left undisturbed?
$(v)$ could be filtered by filter paper?

How will you separate a mixture of common salt $(A)$,camphor $(B)$ and iron filings $(C)$? Describe the process.