Which reagents are used for the identification of Group $IV$ cations?

$A$ colourless crystalline salt $X$ is soluble in dilute $HCl$. On adding $NaOH$ solution,it gives a white precipitate which is insoluble in excess of $NaOH$. $X$ is

In the group $III$ radicals,in place of $NH_4Cl$,which of the following can be used?

$A$ metal salt solution forms a yellow precipitate with potassium chromate in acetic acid,a white precipitate with dilute $H_2SO_4$,but gives no precipitate with $NaCl$. The metal salt solution will consist of:

The correct option$(s)$ to distinguish nitrate salts of $Mn^{2+}$ and $Cu^{2+}$ taken separately is (are):
$(A)$ $Mn^{2+}$ shows the characteristic green colour in the flame test
$(B)$ Only $Cu^{2+}$ shows the formation of precipitate by passing $H_2S$ in acidic medium
$(C)$ Only $Mn^{2+}$ shows the formation of precipitate by passing $H_2S$ in faintly basic medium
$(D)$ $Cu^{2+}/Cu$ has higher reduction potential than $Mn^{2+}/Mn$ (measured under similar conditions)

In the analysis of basic radicals,the group reagent $H_2S$ gas is generally used in which groups?