2N{{H}_{4}}OH\to \] \[\UNDERSET{\left( white\text{ }PPT \right)}{\mathop{Pb{{(OH)}_{2}}}}\,\downarrow +2N{{H}_{4}}N{{O}_{3}}\] \[Pb{{(N{{O}_{3}})}_{2}}+2HCl\to \underset{\left( white\text{ }ppt \right)}{\mathop{PBC{{l}_{2}}\downarrow }}\,+2HN{{O}_{3}}\] \[Pb{{(N{{O}_{3}})}_{2}}+{{H}_{2}}S\to \underset{\left( black \right)}{\mathop{PbS\downarrow }}\,+2HN{{O}_{3}}\]