问题 填空题

在一定条件下进行下列化学反应,请根据以下的转化关系回答下列问题,已知A、B、C中均含有同一种元素.已知:

①若D为金属单质,且以上反应均为氧化还原反应,请写出检验B中阳离子的一种方法______.

②若D为碱,且以上反应均为非氧化还原反应,则A、B、C、D分别可以是:(按顺序写出合理的一组物质的化学式即可)A______,B______,C______,D______.

③D为碱时,写出A和C反应的离子方程式______.

答案

根据题给反应关,系,①若D为金属单质,则可以是锌,A可以是FeCl3,锌适量时,Zn+2FeCl3=ZnCl2+2FeCl2;锌过量时,Zn+FeCl2=ZnCl2+Fe,且Fe+2FeCl3=3FeCl2符合题意,所以B为FeCl2,检验B中金属离子的方法是:向其溶液中滴加NaOH溶液,出现白色沉淀,迅速变为灰绿色,最后变为红褐色,则其溶液中有Fe2+

故答案为:向其溶液中滴加NaOH溶液,出现白色沉淀,迅速变为灰绿色,最后变为红褐色,则其溶液中有Fe2+;(或向其溶液中加入硫氰酸钾溶液,无变化,加入氯水变红证明二价铁离子的存在)

②若D为碱,且以上反应均为非氧化还原反应,所以与碱能发生连续反应的最典型的物质是Al3+,则A可以是AlCl3,B是Al(OH)3,C是NaAlO2,D为NaOH;故答案为:A是AlCl3,B是Al(OH)3,C是NaAlO2,D为NaOH;

③D为碱时,A和C反应是氯化铝和偏铝酸钠反应生成氢氧化铝沉淀,所以反应的离子方程式为:Al3++3AlO2-+6H2O=4Al(OH)3↓;故答案为:Al3++3AlO2-+6H2O=4Al(OH)3↓;

阅读理解
School BBS (校园论坛)
Topics(话题): Ask for help
Lily
I’m shy. I want to talk to my classmates, but I am afraid they will laugh at me. What should I do?
Simon
There are so many net bars(网吧) around us. I spend too much time and money in playing computer games. I can’t pass the exams. My parents are angry with me. What should I do?
Tom
Father’s Day is coming. My father is good at playing basketball. He also likes to watch films. What present should I give to my father?
Jim
I like Chinese. I am good at Chinese. I often win the writing competition(竞赛). But my English is not good. I can’t speak English well. What should I do to learn English well?
小题1:The topic of the BBS is             .
A.how to learn English
B.to ask for help
C.how to make friends
D.Don’t play computer games.
小题2:If you want to help Simon, what should he do ?
A.Don’t play computer games any more, and spend more time on lessons.
B.Go on playing computer games.
C.Don’t play computer games in the net bars, just play games at home.
D.Pay no attention to (不在意) parents and teachers.
小题3:Which is the best present for Tom’s father?
A.A coat.B.A pair of sports shoes.
C.Some flowers.D.Some story books.
小题4:Which is Jim’s favourite subject?
A.EnglishB.ChineseC.MathsD.PE
小题5:If you have problems, what will you do?
A.Don’t tell anyone about your problems.
B.Have a talk to your classmates and ask them to help you.
C.Pay no attention to (不在意) them.
D.B and C
读图填空题