$A$ miscible mixture of $C_6H_6 + CHCl_3$ can be separated by

$A$ mixture of $ZnCl_2$ and $PbCl_2$ can be separated by

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

The separation of two coloured substances was done by paper chromatography. The distances travelled by solvent front,substance $A$ and substance $B$ from the base line are $3.25 \ cm$,$2.08 \ cm$ and $1.05 \ cm$ respectively. The ratio of $R_{f}$ values of $A$ to $B$ is $.........$

Percentage of lead in lead pencil is

$A$ mixture of sodium chloride and ammonium chloride is separated by: