A:氨水显碱性:NH3•H2O═NH4++OH﹣
B:Na2S溶液显碱性:S2﹣+2H2O⇌H2S+2OH﹣
C:硫酸氢钠溶液显酸性:NaHSO4═Na++H++SO42﹣
D:AlCl3溶液显酸性:Al3++3H2O⇌Al(OH)3↓+3H+