Which of the following basic radicals will not be precipitated by $H_2S$ gas in the presence of $NH_3$?

$A$ solution,when diluted with $H_2O$ and boiled,gives a white precipitate. On the addition of excess $NH_4Cl / NH_4OH$,the volume of the precipitate decreases,leaving behind a white gelatinous precipitate. Identify the precipitate which dissolves in $NH_4OH / NH_4Cl$.

$A$ pink coloured salt turns blue on heating. The presence of which cation is most likely?

Identify the inorganic sulphides that are yellow in colour $ : $
$(A)$ $(NH_4)_2S$
$(B)$ $PbS$
$(C)$ $CuS$
$(D)$ $As_2S_3$
$(E)$ $As_2S_5$
Choose the correct answer from the options given below $ : $

When calomel reacts with a solution of $NH_4OH$,which compound is formed?

Which of the following cations will give a precipitate with $Na_2C_2O_4$ solution in the presence of acetic acid?