题干

2015年8月12日天津港危化品爆炸,教训极为深刻.其中化学品之一是氰化钠(NaCN):白色固体,可溶于水,剧毒,致死量50~250mg.氰化钠遇水或酸生成剧毒易燃的氰化氢(HCN)气体.处理氰化物可用碱性氯化法,该方法发生三步反应,写出其离子方程式.

①氯气与氢氧化钠溶液反应生成次氯酸盐(ClO﹣):____.

②次氯酸盐氧化氰化物(CN﹣)生成氰酸盐(CNO﹣):ClO﹣+CN﹣=CNO﹣+2Cl﹣

③过量的次氯酸盐在碱性溶液中氧化氰酸盐生成CO32﹣和N2:____.

上一题 下一题 0.0难度 选择题 更新时间:2019-08-17 05:02:55

答案(点此获取答案解析)

Cl2+2OH\ufe63=Cl\ufe63+ClO\ufe63+H2O,3ClO\ufe63+2CNO\ufe63+2OH\ufe63=3Cl\ufe63+2CO32\ufe63+N2\u

同类题5

阅读理解

    I have a friend named Monty Roberts who owns a horse ranch(牧马场). The last time I was there he told me his story. When he was young, his family was too poor to have a house to live in.As a result , when he was in high school, all the students were asked to write a paper about what they wanted to be and do when they grew up. That night he wrote a seven-page paper describing his goal of owning a horse ranch. He also drew a picture to show a 4,000-square-foot house that would sit on a beautiful farm. The next day he handed it in to his teacher. Two days later he received his paper back. On the front page was a large red F. Roberts asked, “Why did I receive an F?” He teacher said, “This is an unrealistic dream for a young boy like you. Owning a horse ranch requires a lot of money.” Then the teacher added, “If you will rewrite this paper with a more realistic goal, I will reconsider your grade.”

    The boy went home and thought about it for a long and hard time. He asked his father what he should do. His father said, “ Look, son, you have to make up your own mind on this. However, I think it is a very important decision for you.”Finally, after sitting with it for a week, the boy turned in the same paper, making no changes at all. He told his teacher “you could keep the F and I still keep my dream”.

    He tells me this story because I am sitting in his 4,000-square-foot house in the middle of the 200-acre horse ranch. “I still have that school paper now.” He added, “The best part of the story is that two years ago that  teacher brought 30 kids to camp out on my ranch for a week.” When the teacher was leaving, he said, Look, Monty, I can tell you this now. When I was your teacher, I was something of a dream stealer.During those years I stole a lot of kids' dreams. Luckily, you had enough gumption not to give up on yours. .”