二氧化硫是重要的工业原料，探究其制备方法和性质具有非常重要的意义．

（1）工业上用黄铁矿（FeS₂，其中S元素为﹣l价）在高温下和氧气反应制备SO₂：4FeS₂+11O₂═8SO₂+2Fe₂O₃，该反应中被氧化的元素是____ （填元素符号）．当该反应转移2.75mol电子时，生成的二氧化硫在标准状况下的体积为____ L．

（2）实验室中用如图1所示的装置测定SO₂催化氧化为SO₃，的转化率．（已知SO₃熔点为16.8℃，假设气体进入装置时分别被完全吸收，且忽略空气中CO₂的影响．）

①简述使用分液漏斗向圆底烧瓶中滴加浓硫酸的操作是____ ．

②实验过程中，需要通入氧气．试写出一个用图2所示装置制取氧气的化学方程式____ ．

③当停止通入SO₂，熄灭酒精灯后，需要继续通一段时间的氧气，其目的是____ ．

④实验结束后，若装置D增加的质量为m g，装置E中产生白色沉淀的质量为ng，则此条件下二氧化硫的转化率是____ （用含字母的代数式表示，不用化简）．

（3）某学习小组设计用如图3装置验证二氧化硫的化学性质．

①能说明二氧化硫具有氧化性的实验现象为____ ．

②为验证二氧化硫的还原性，充分反应后，取试管b中的溶液分成三份，分别进行如下实验：

方案I：向第一份溶液中加入AgNO₃溶液，有白色沉淀生成

方案Ⅱ：向第二份溶液加入品红溶液，红色褪去

方案Ⅲ：向第三份溶液加入BaCl₂溶液，产生白色沉淀

上述方案中合理的是____ （填“I”、“Ⅱ”或“Ⅲ”）；试管b中发生反应的离子方程式为____ ．

根据短文理解，选择正确答案。

    My husband hasn't stopped laughing about a funny thing that happened to me. It's funny now but it wasn't at the time.

    Last Friday, after doing all the family shopping in town, I wanted a rest before catching the train, so I bought a newspaper and some chocolate and went into the station coffee shop — that was a cheap self-service place with long tables to sit at. I put my heavy bag down on the floor, put the newspaper and chocolate on the table to keep a place, and went to get a cup of coffee.

    When I went back with the coffee, there was someone in the next seat. It was one of those wild-looking youngsters, with dark glasses and worn clothes, and hair colored bright red at the front. Not so unusual these days. What did surprise me was that he'd started to eat my chocolate!

    Naturally, I was annoyed. However, to avoid trouble — and really I was rather uneasy about him — I just looked down at the front page of the newspaper, tasted my coffee and took a bit of chocolate. The boy looked at me closely. Then he took a second piece of my chocolate. I could hardly believe it. Still I didn't dare to start an argument. When he took a third piece, I felt more angry than uneasy. I thought, "Well, I shall have the last piece." And I got it.

    The boy gave me a strange look, and then stood up. As he left he shouted out. "This woman's crazy!" Everyone stared. That was embarrassing enough, but it was worse when I finished my coffee and got ready to leave. My face went red — as red as his hair — when I realized I'd made a mistake. It wasn't my chocolate that he'd been taking. There was mine, unopened, just under my newspaper.

我会填

①英：共____画 第三笔是____  

②静：共____笔，部首是____。