The technique used for purification of steam volatile water immiscible substances is :

In the wet tests for detection of various cations by precipitation, $$\mathrm{Ba}^{2+}$$ cations are detected by obtaining precipitate of

When a solution of mixture having two inorganic salts was treated with freshly prepared ferrous sulphate in acidic medium, a dark brown ring was formed whereas on treatment with neutral $$\mathrm{FeCl}_{3}$$, it gave deep red colour which disppeared on boiling and a brown red ppt was formed. The mixture contains :

In Carius tube, an organic compound '$$\mathrm{X}$$' is treated with sodium peroxide to form a mineral acid 'Y'.

The solution of $$\mathrm{BaCl}_{2}$$ is added to '$$\mathrm{Y}$$' to form a precipitate 'Z'. 'Z' is used for the quantitative estimation of an extra element. '$$\mathrm{X}$$' could be