题干

下列说法不正确的有(   )

①除去二氧化碳中混有的少量氧气,可以通入一氧化碳后点燃,将氧气转化为二氧化碳

②实验室用6%的氯化钠溶液配制3%的氯化钠溶液,量取6%的氯化钠溶液时俯视读数,若其他操作均正确,则所配溶液中溶质的质量分数大于3%

③某固体可能由氯化钠、硫酸钠、氯化钡、氯化镁、硫酸钾中的一种或几种组成,取少量该固体,加入足量的稀氢氧化钠溶液,产生白色沉淀,过滤,向沉淀中加入足量稀硝酸,沉淀部分溶解,则该固体的组成有5种情况

④某碳酸钠溶液中可能含有另一种溶质,取一定量该溶液,逐滴滴加稀盐酸,产生气体的体积与加入稀盐酸的体积关系如图所示,则该碳酸钠溶液中一定含有氢氧化钠.

A:1种

B:2种

C:3种

D:4种

上一题 下一题 0.0难度 选择题 更新时间:2010-05-24 11:51:59

答案(点此获取答案解析)

D

同类题1

阅读短文,掌握其大意,选择可以填在横线上的最佳选项。

    It was a fine spring day with beautiful flowers in the park. A young man arrived early and waited for his 1 under a big tree. But he was so short-tempered (性急的) that he wasn't in the mood to 2 the scenery.

    Suddenly, an angel appeared, "Here is a button (按钮). If you don't want to 3, just turn the button to the right. You can skip over (跳过) any time period if you want to."

    The man happily held the button and turned it softly. Oh! How amazing! His girlfriend appeared before him and was gently 4 him! "How I wish our wedding ceremony could be held now!" He turned the button once again. A great wedding 5 in front of him. The beautiful bride (新娘) was standing next to him and the band was playing 6 music. He lost himself in it deeply.

    The 7 in his heart kept coming out: I also want a big house with a garden in the front. He turned the button. Then he wished for children. All of a sudden, a group of lovely children were playing 8 in the huge living room. Again, he jumped at the chance to tum the button to the right.

    How time flew! Before he could see beautiful flowers in the garden, everything had been covered in deep snow. Looking at himself again, he found his hair totally 9. He had already become so old.

    He felt so sad. He would rather enjoy life step by step than watch it go by in such a hurry. He quickly turned the button to the 10.

    Once again, he was waiting for his lovely girlfriend under that big tree.