A.20-27 B.23-27 C.27-30 D.30-33
A.1/2 B.1/3 C.2/3 D.3/4
A.質(zhì)量分?jǐn)?shù)為98%的濃硝酸 B.碳酸氫銨 C.氨水 D.甲醛