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 :

Given below are two statements:

Statement I : If BOD is 4 ppm and dissolved oxygen is 8 ppm, then it is a good quality water.

Statement II : If the concentration of zinc and nitrate salts are $$5 ~\mathrm{ppm}$$ each, then it can be a good quality water.

In the light of the above statements, choose the most appropriate answer from the options given below :

Match List-I with List-II:

Choose the correct answer from the options given below :

Thin layer chromatography of a mixture shows the following observation:

The correct order of elution in the silica gel column chromatography is