Which are valid ways to make an ammonia/ammonium buffer for use in the laboratory? Mix some volume of 1 M NH 3 1 M NH3 with half as much 1 M HCl . 1 M HCl. Mix equal volumes of 1 M NH 3 1 M NH3 and 0.01 M NH + 4 . 0.01 M NH4+. Mix equal volumes of 1 M NH 3 1 M NH3 and 1 M HCl . 1 M HCl. Mix equal volumes of 1 M NH 3 1 M NH3 and 1 M NH + 4 .