In the precipitation of the iron group (III) in qualitative analysis, ammonium chloride is added before adding ammonium hydroxide to :

The compound that is white in color is

Given below are two statements :

Statement (I) : The gas liberated on warming a salt with dil $$\mathrm{H}_2 \mathrm{SO}_4$$, turns a piece of paper dipped in lead acetate into black, it is a confirmatory test for sulphide ion.

Statement (II) : In statement-I the colour of paper turns black because of formation of lead sulphite. In the light of the above statements, choose the most appropriate answer from the options given below :

Appearance of blood red colour, on treatment of the sodium fusion extract of an organic compound with $$\mathrm{FeSO}_4$$ in presence of concentrated $$\mathrm{H}_2 \mathrm{SO}_4$$ indicates the presence of element/s