Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$AlCl_3 + Na_3PO_4 \longrightarrow AlPO_4 \downarrow$

Lead sulphate is soluble in:

When $MgSO_4$ is treated with $NH_4OH$ and $Na_2HPO_4$,a white crystalline solid is formed. What is its formula?

Choose an incorrect match of the colour of compounds.

The pair$(s)$ of ions where $BOTH$ the ions are precipitated upon passing $H_2S$ gas in the presence of dilute $HCl$,is(are):
$(A) Ba^{2+}, Zn^{2+}$
$(B) Bi^{3+}, Fe^{3+}$
$(C) Cu^{2+}, Pb^{2+}$
$(D) Hg^{2+}, Bi^{3+}$

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