Precipitate of group $IV$ cations takes place when $H_2S$ is

$A$ solution prepared in conc. $HCl$ sometimes gives white turbidity even in the absence of $1^{st}$ group,when water is added to it. It is due to the presence of

Which of the following is not precipitated as sulphide by passing $H_2S$ in the presence of concentrated $HCl$?

The reagents $NH_4Cl$ and aqueous $NH_3$ will precipitate which of the following ions?

$A$ salt '$A$' which gives a green flame with a Bunsen burner,on reaction with dil. $H_2SO_4$ produces gas $(2)$ and white turbidity $(Z)$. The saturated solution of gas $(2)$ on reaction with $H_2S$ gas produces '$Z$'. Then select the $CORRECT$ statement.

$A$ mixture of chlorides of $Cu, Cd, Cr$ and $Fe$ was dissolved in water acidified with dil. $HCl$ and $H_2S$ gas was passed. It was filtered,and boiled later adding two drops of $HNO_3$. To this solution $NH_4Cl$ and $NH_4OH$ (or $NaOH$ in excess) were added. The filtrate shall give a test for :-