A.0.2mol/LHCl B.0.2mol/LH2SO3 C.0.4mol/LHCl D.0.2mol/LH2CO3
A.酚酞指示劑 B.甲基橙指示劑 C.金屬指示劑 D.酸堿指示劑
A.5% B.10% C.15% D.20%