问题 实验题

工业含铬(Cr)废水的处理原理是将Cr2O72-转化为Cr3+,再将Cr3+转化为沉淀。废水pH与Cr2O72-转化为Cr3+的关系如图1,实验室模拟工业电解法处理含铬废水的装置如图2

请根据以上知识回答下列问题:

(1)含铬废水预处理的方法是___________________________。

(2)在图2中连接铁棒的一极是电源的_________极。

(3)实验中除能观察到废水颜色发生变化外,还能观察到的现象是___________________________。

表一:

(4)当废水颜色不再发生明显变化时,切断电源,取出电极,再调节电解液的pH至8左右。调节pH的目的是___________________________。

(5)含铬废水国家排放标准为含量≤0.1000mg/L。取上述电解后的废水200.00mL,调节pH=1后置于锥形瓶中,用浓度为0.0001mol/L的KI溶液滴定,至滴定终点时,用去KI溶液9.00mL。已知酸性条件下,I-

Cr2O72-氧化的产物为I2。用计算所得数据说明上述电解法处理后的废水是否符合国家排放标准____________________________________。

答案

(1)调节pH为1左右

(2)正 

(3)阴极区产生沉淀

(4)使溶液中的Fe3+、Cr3+全部转化为氢氧化物沉淀

(5)经计算知,上述电解后的废水中含量=0.0780mg/L,符合国家排放标准

阅读理解

阅读理解。

     Jane Austen, a famous English writer, was born at Steventon, Hampshire, on December 16, 1775, and died

on July 18, 1817. She began writing early in life, although the prejudices of her times forced her to have her

books published anonymously ( 匿名 ).

     But Jane Austen is perhaps the best known and best loved of Bath's many famous local people and visitors.

She paid two long visits here during the last five years of the eighteenth century and from 1801 to 1806, Bath

was her home. Her deep knowledge of the city is fully seen in two of her novels, Northanger Abbey and

Persuasion, which are largely set in Bath. The city is still very much as Jane Austen knew it, keeping in its

streets and public buildings the well-ordered world that she described so well in her novels. Now the pleasure

of learning Jane Austen's Bath can be enhanced (增强) by visiting the Jane Austen Centre in Gay Street. Here,

in a Georgian town house in the heart of the city, you can find out more about Bath in Jane Austen's time and

the importance of Bath in her life and work.

     The Centre has been set up with the help and guidance of members of the Jane Austen Society. After your

visit to the Centre, you can look round the attractive shop, which offers a huge collection of Jane Austen

related books, cards and many specially designed gifts. Jane Austen quizzes are offered to keep the children

busy.

     You can also have walking tours of Jane Austen's Bath, which is a great way to find out more about Jane

Austen and discover the wonderful Georgian city of Bath. The tour lasts about one and a half hours. The

experienced guides will take you to the places where Jane lived, walked and shopped.

1. Jane Austen paid two long visits to Bath ______.

A. in her early twenties

B. in her early teens

C. in her late twenties

D. in her late teens

2. What can we learn about Bath from the passage?

A. Bath has greatly changed since Jane Austen's death.

B. The city has changed as much as Jane Austen knew it.

C. Bath remains almost the same as in Jane Austen's time.

D. No changes have taken place in Bath since Jane Austen's time.

3.The author writes this passage in order to ______.

A. attract readers to visit the city of Bath

B. ask readers to buy Austen's books

C. tell readers about Jane Austen's experience

D. give a brief introduction to the Jane Austen Society

4. It takes you about one and a half hours ______.

A. to get to the Jane Austen Centre in Gay Street

B. to buy Jane Austen related books, cards and gifts

C. to find a guide to take you to the Centre

D. to look around the city of Bath on foot

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