Passing H2S in the presence of NH4OH is group reagent for Group IV cations - Mn2+ NH4OH in the presence of NH4Cl is group reagent for Group III cations - Al3+ Passing H2S in the presence of HCl is Group reagent for group II cations - Cu2+ (NH4)2CO3 in the presence of NH4OH is used for detection of Ba2+ P⟶3;Q⟶4;R⟶2;S⟶1