$A$ reagent used to test the presence of $Fe^{2+}$ ion is

Compound $X$ is tested and the results are shown in the table.

Test	Result
Aqueous $NaOH$ is added, then heated gently.	Gas given off which turns damp red litmus paper blue.
Dilute $HCl$ is added.	Effervescence, gas given off which turns lime water milky and acidified $K_2Cr_2O_7$ paper green.

Which ions are present in compound $X$?

$A$ metal nitrate reacts with $KI$ to give a black precipitate which on addition of excess of $KI$ converts into an orange-colored solution. The cation of the metal nitrate is

$A$ precipitate of ....... would be obtained on adding $HCl$ to a solution of $(Sb_2S_3)$ in yellow ammonium sulphide.

Identify $A$,$B$ and $C$ in the given reaction sequence.

Which of the following is an incorrect match for the precipitate (ppt) and its color?