[题目]实验室制备硝基苯的主要步骤如下:①配制一定比例的浓硫酸与浓硝酸的混合酸.加入反应器中,②向室温下的混合酸中逐滴加入一定量的苯.充分振荡.混合均匀,③在50-60℃下发生反应.直至反应结束,④除去混合酸后.粗产品依次用蒸馏水和5%NaOH溶液洗涤.最后再用蒸馏水洗涤,⑤将用无水CaCl2干燥后的粗硝基苯进行蒸馏.得到纯净的硝基苯.请填写下列空� 题目和参考答案——青夏教育精英家教网—

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【题目】实验室制备硝基苯的主要步骤如下：①配制一定比例的浓硫酸与浓硝酸的混合酸，加入反应器中；②向室温下的混合酸中逐滴加入一定量的苯，充分振荡，混合均匀；③在50～60℃下发生反应，直至反应结束；④除去混合酸后，粗产品依次用蒸馏水和5%NaOH溶液洗涤，最后再用蒸馏水洗涤；⑤将用无水CaCl2干燥后的粗硝基苯进行蒸馏，得到纯净的硝基苯。

请填写下列空白：

(1)配制一定比例浓硫酸和浓硝酸混合酸时，操作的注意事项是__________________。

(2)步骤③中，为了使反应在50～60℃下进行，常用的方法是____________________。

(3)步骤④中洗涤、分离粗硝基苯应使用的仪器是___________________________。

(4)步骤④中粗产品用5%NaOH溶液洗涤的目的是____________________________。

(5)纯硝基苯是无色，密度比水______(填“大”或“小”)，具有________气味的油状液体。

【答案】(1)先将浓硝酸注入容器中，再慢慢注入浓硫酸，并及时搅拌和冷却

(2)将反应器放在50～60℃(或60℃)的水浴中加热

(3)分液漏斗

(4)除去粗产品中残留的酸

(5)大苦杏仁

【解析】配制一定比例浓硫酸和浓硝酸混合酸的操作与浓硫酸的稀释操作相似。使反应在50～60℃下进行，常用的方法是水浴加热。硝基苯是不溶于水的液体，用分液的方法分离。粗产品用5%NaOH溶液洗涤的目的是除去未反应的酸。纯硝基苯的密度比水大，具有苦杏仁气味。

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Do you like visiting museums? Here are some of the best museums in the world.

The Rijksmuseum in Amsterdam is the largest and most famous museum for art and history in Holland. It has a large collection of paintings from the Dutch Golden Age, including works by Vermeer and Rembrandt. Until 2013, the museum is being completely restored, but the major great works are still on show.

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Founded in 1764 by Catherine the Great, the Hermitage Museum in Saint Petersburg, Russia is a large museum of art and culture. It shows a collection of over 3 million items throughout the world. Being a popular tourist attraction, the Hermitage is truly one of the best museums in the world. It displays priceless works by Rembrandt, Da Vinci, Michelangelo, Reubens and more.

Built in 1753, the British Museum in London is a museum of human history and culture. Its collections, which include more than seven million objects, are among the largest in the world. Objects include the Rosetta Stone and the largest collection of mummies outside Egypt. It’s one of the top destinations in London.

Home to at least 120, 000 items of ancient Egyptian antiquities(古迹), the Egyptian Museum in Cairo is one of the world’s best museums. There are two main floors, the ground floor and the first floor. On the ground floor there is a collection of coins used by the ancient Egyptians. On the first floor there are artifacts from the final two dynasties of Ancient Egypt and also many artifacts taken from the Valley of the Kings.

【1】 If you want to see Van Gogh’s works in the most influential museum of modern art in the world, you should go to_____________.

A. London B. New York City

C. Amsterdam D. Saint Petersburg

【2】What do we know about the Hermitage Museum in Saint Petersburg, Russia?

A. It was built by Catherine the Great in the 17th century.

B. The items displayed in the museum are all worthless.

C. It displays a collection of over 3 million items from Russia.

D. Works of Da Vinci and Reubens can be seen there.

【3】 We learn that the Egyptian Museum in Cairo_____________.

A. is much larger than the others mentioned

B. has more items than the others mentioned

C. is one of the top destinations in the world

D. mainly displays ancient Egyptian antiquities

【4】 What’s the writer’s purpose in writing the passage?

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B组	红花×白花	红花︰白花=7︰1
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（2）试解释A组结果没有出现3︰1性状分离比的原因．

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