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

Which of these reactions is correct?

Formation of which complex,among the following,is not a confirmatory test of $Pb^{2+}$ ions?

$A$ white crystalline substance dissolves in water. On passing $H_2S$ in this solution,a black precipitate is obtained. The black precipitate dissolves completely in hot $HNO_3$. On adding a few drops of conc. $H_2SO_4$ a white precipitate is obtained. This precipitate is that of:

$A \xrightarrow{ K_4[Fe(CN)_6] } \text{Blue-white precipitate}$. Which ion is $A$?

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 $ : $