\(H_{2}\)S gas changes a filter paper dipped in lead acetate solution into :-
Black
Red
Green
Yellow

When lassaigne's extract (Na_(2)S) is acidified with acetic acid and then lead acetate solution is added to it, the colour of the precipitate is

The sodium extract on acidification with acetric acid and then adding lead acetate solution gives a black precipitate. The organic compound contains.

The sodium extract of an organic compound on acidification with acetic acid and addition of lead acetate solution gives a black precipitate . The organic compound contains ________.

Which one of the following cations will give a green coloured ash when a piece of filter paper dipped in a solution containing its salt and Co(NO_(3))_(2) is burned?