搜题请搜索小程序“爱下问搜题”
问题 选择题

足量的金属铁与下列酸溶液反应，初始反应速率最快且最终产生氢气最多的是

A．100mL0.1mol/L盐酸

B．100mL0.2mol/L硝酸

C．75 mL0.2mol/L盐酸

D．20mL18.4mol/L硫酸

答案

答案：C

B、D中的酸为强氧化性酸，与铁不会产生氢气，而A、C相比，C中氢离子的浓度较大，故产生氢气的速率最大。

改错题

短文改错。

     下面短文中有10处语言错误。请在有错误的地方增加、删除或修改某个单词。

     增加：在缺词处加一个漏字符号（∧），并在其下面写上该加的词。

     删除：把多余的词用斜线（\）划掉。

     修改：在错的词下划一横线，并在该词下面写上修改后的词。

     注意：1.每处错误及其修改均仅限一词。

                 2.只允许修改10处，多者（从第11除起）不计分。

      I love camping. It is my favoritest way to spend the summer vacation. Last year, my family and I

went camping in the countryside. It was one of the most excited experiences I had never had. We slept

in a tent and went on a long walk every day. We cook over a fire and the food always tasted wonderfully. For a whole week, I saw lovely mountain views or breathed fresh air. At night, I heard the gentle wind

blowing in the tree, and I felt so peaceful. It doesn't cost many to camp, and what I believe it's the best

way to get close nature and enjoy its beauty.      

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单项选择题

如遇刮板输送机不平区段，应（）进行处理后再作业。

A.超前

B.稍后

C.不用

D.以上均可
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