Which reagent is used to distinguish between silver and lead salts?

An aqueous solution of a salt $X$ turns blood red on treatment with $CNS^{-}$ and blue on treatment with $K_4[Fe(CN)_6]$. $X$ also gives a positive chromyl chloride test. The salt $X$ is

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

In the analysis of Group-$II$ basic radicals,$H_2S$ gas is passed in the presence of dilute $HCl$ because...

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:

$A$ mixture of $NaCl$ and $K_{2}Cr_{2}O_{7}$ is heated with conc. $H_{2}SO_{4}$,deep red vapours are formed. Which of the following statements is false?