简述缓蚀剂的作用。
参考答案:
缓蚀剂的作用有:
1.降低酸耗;
2.提高金属收得率;
3.防止过酸洗;
4.减少环境污染;
5.改善酸洗质量。
小题1:She always c (抱怨) about the dirty room.
小题2:He worked in a few f (工厂) ten years ago.
小题3:The old woman c (不能) go to the park yesterday.
小题4:She was riding her bike when a car a happened.
小题5:It’s (令人惊异的) to see such a strange dog.
将浓硫酸和稀硫酸在实验室中分别敞口放置。它们的质量和放置天数的关系如右图,分析a、b曲线变化的原因是 ( )。
A.a挥发、b吸水
B.a升华、b冷凝
C.a蒸发、b潮解
D.a冷凝、b吸水