When $H_2S$ is passed through a solution in $Group-II$ analysis,it sometimes becomes milky. This indicates the presence of:

On treating a solid salt $A$ with dil. $H_2SO_4$ and warming,reddish-brown fumes of gas $B$ are evolved. Addition of $C$ to the salt solution of $A$ followed by freshly prepared starch solution and acidification with acetic acid produces a blue colour. $C$ may contain:

An aqueous solution containing $FeSO_4$,$Al_2(SO_4)_3$,and chrome alum is treated with $Na_2O_2$ and heated,followed by filtration. The resulting products are:

What is formed when calomel $(Hg_2Cl_2)$ reacts with $NH_4OH$?

The solution of $BiCl_{3}$ in dil. $HCl$ when diluted with water,forms a white precipitate which is:

$A$ salt with a few drops of conc. $HCl$ gives an apple green colour in a flame test. The group precipitate of the salt is dissolved in acetic acid and treated with $K_{2}CrO_{4}$ to give a yellow precipitate. When the sodium carbonate extract of the salt solution is heated with conc. $HNO_{3}$ and ammonium molybdate,it results in a canary yellow precipitate. The cation and anion present in the salt are respectively,