What type of mixture is an alloy? Explain.

In a closed container,there is a mixture of $SO_2$,$CO_2$,and $O_2$ gases. Which sequence of reagents can be helpful to separate them?
$(I)$ Limewater
$(II)$ Acidified potassium dichromate
$(III)$ Alkaline pyrogallol

On the basis of which physical property does the separation of different fractions in the fractional distillation technique take place?

Which of the following substances sublimes upon heating?

Which method is used to separate a mixture of $KCl$ and $KClO_3$?

Which of the following substances undergoes sublimation?