A.35% B.58% C.78% D.90%
A.33% B.45% C.55% D.60%
H2S04質(zhì)量分?jǐn)?shù)控制在()時(shí)酸的活性最強(qiáng),即酸洗時(shí)間最短。
A.15% B.25% C.35% D.45%