题干

乙酸的下列性质中,可以证明它是弱电解质的是(  )

A:乙酸与水能以任意比例互溶

B:乙酸溶液的导电性弱

C:10 mL1 mol•L﹣1乙酸恰好与10 mL1 mol•L﹣1NaOH溶液完全反应

D:1 mol•L﹣1的乙酸溶液的C(H+)约为0.01 mol•L﹣1

上一题 下一题 0.0难度 选择题 更新时间:2019-12-12 02:14:28

答案(点此获取答案解析)

D

同类题4

    In the most southern part of our planet, there's a place that's covered with snow and ice all year round. But it has the clearest and cleanest air. Amazingly, in this place, the sun sometimes hangs even in the midnight sky. This place is Antarctica (南极洲): the coldest, windiest and harshest (恶劣的) place on the Earth.
    As the world's least-known place, Antarctica is of great interest to scientists around the world. In 1983, China joined the Antarctic Treaty (《南极条约》). The treaty made Antarctica a peaceful place for member countries to do scientific research. During 30 years, China has sent many scientists to Antarctica. They mostly look at the resources under the icy land and do research about climate change and marine (海洋的) biology.
    Antarctica is a place with fantastic views. However, life there is very hard. Food is one of the biggest problems. Frozen (速冻) food which can be heated easily is people's daily food. Fresh vegetables are hard to grow in the cold weather. Therefore, scientists often eat dried or canned vegetables.
    Sleep is also troublesome. In Antarctica, summer lasts from November to March. During this period, Antarctica points to the sun and receives sunlight 24 hours a day. In order to get some sleep, scientists cover the windows with black plastic cloth to create “night”.
Working in Antarctica is dangerous, especially when meeting gale-force (七级以上的) winds. Sometimes the wind is even stronger than a typhoon. It can easily blow people away. So there are ropes that connect buildings of some research stations. People can hold these ropes to keep their balance in forceful winds.
    What's more, communicating with others is difficult. Without cables and Internet in some research stations, two-way radios are the only tools to communicate. If people want to say hello to friends and relatives, they can use satellite phones.
    Although it is challenging to work in Antarctica, scientists' passion to learn about this mysterious land will never end. It is hopeful that one day they will step every corner of this icy land.

同类题5

阅读下面的文字,完成问题。

“铁拐李”传奇

陈圣芳

    他,拄着拐杖,个子瘦瘦高高的,是一个流浪乞丐,身背很多口袋的褡祾,每天走村串户地乞讨,像一个行脚僧,人们背地里都叫他“铁拐李”。

    “铁拐李”讨米很特别,用手抓的米他是断然不会要的。原来一个刁顽尖滑的大嫂,把一只紧捏的空手放进米袋子,然后从他袋子里面带出一大把米来。

    铁拐李乞讨没有定性,走哪是哪。天黑了,随便睡在学校或者队屋廊檐下,将身子蜷缩成大虾米,囫囵睡去。当天放明时,又不知所踪了。而一方方的墙壁上,却用土坷垃划写满了诗文。湾子里的斋儒老先生曾经教过私塾,他一手捻着他那稀稀落落的几缕白胡子,一边摇头晃脑地吟哦着,一脸的陶醉。

    “铁拐李”他有时也会给几分钱湾里的剃头匠,让剃头匠将他那乱茅草一样的头发理得顺顺当当的,但是他那飘然若仙的胡子他是一定不会剪的,而且,他每次去河边洗碗时,都会把胡子润湿,对着水面捊了又捊。然后把碗刷的贼亮,像猫子舔了似的。

    “铁拐李”虽然疯癫时六亲不认,举起拐杖见人就打,见狗就追。一旦安静下来,他又特别喜欢孩子。那天他在苕货家门口发现苕货在写字,便蹑手蹑脚笑眯眯地走了过去,在后面认真地端详着,并且细声细气地告诉苕货:你发倒笔了,这个勾是“利刀勾”,这个不是这样的,是“宝盖头”,上面没有一点……他告诉苕货很多以后,当再遇见苕货时,他还不忘在他的草稿纸上教几个字,过几天他回来时,他一定会考考苕货,如果苕货回答正确了,他会像变戏法一样,变出一把把花花绿绿的豌豆糖来,赏给苕货。

    有段时间,“铁拐李”突然不疯癫了,他居然背了一个上面印有“好好学习 天天向上 ***”的书包,一步一拐地走学校赶乡集,卖他用澴河潭坡上的泥巴做出来的口哨。

    那泥巴做的口哨的确精妙绝伦,有高音的,有中音的,也有低音的,五颜六色,煞是好看。如果那个小朋友吹的好,他会摸摸他的小脑袋,笑眯眯地说,拿去吧,不要钱。得到哨子的孩子像过年般的高兴,于是刹那间,满湾子从南到北都是“蛐蛐”般忽高忽低的泥巴口哨声。不过,他尤其喜欢苕货,他看见苕货往往会送他几个五颜六色的泥巴哨,并且还要当面给苕货做示范,同是“蛐蛐”几声,却别有一番韵味。等到学生上课后,他就默默地站在教室的廊檐下,看着琅琅读书的孩子,一脸笑意。有一次,他在走廊小黑板前伫立良久,然后捡起地上的粉笔头,在黑板上涂改起来。一个老师发现了,便吼了几声,吓得铁拐李一溜烟跑了。那老师过来一看却愣住了,原来他修改了一处语法错误。

    从此以后,这位老师便特别关注起铁拐李来。有一天,他路过铁拐李寄住的废砖窑时,看到一个漂亮的城里女子,对着铁拐李声泪俱下地说着什么,而他却有滋有味吃着讨来的米饭,理也不理。后来那女子伸手去拉铁拐李,不料一下子惹恼了他,他挥舞着拐杖,吼道:“你滚,你滚,我不要你管……”那位老师忙躲到一边,看见那女人一步一回头地离开了废砖窑。后来听人说铁拐李原来是一所大学的教授,因为说错了一句什么话划成右派,加上妻子闹离婚,所以就成了流浪的疯子;还有的人说,那个女人是他的学生,很是崇拜他,知道了恩师落脚地后,踏破铁鞋不远千里赶到这里……打这天起,铁拐李就突然从人们的视线里悄然消失了。

    开始还有人念叨一下:铁拐李好长时间没有来讨饭哩?再后来,铁拐李这个名字就像从澴河上游冲下来的一截树枝,在河湾汊里打个转顺流而下,一去无踪。

    而当“铁拐李”这个名字,再次被人提起时,已是十几年后的一天了。那天,已考取博士生的苕货,给家里寄来一张他和导师以及师母的合影。邻居们呼啦一下子围过来看,马上有人说:“咦!师母好年轻啊,怕要比导师年轻不少哩。”突然有人叫了一声:“这苕货的导师,有点像铁拐李呢。”大伙围过来一看,“呵呵,别说,还真有点像哩!”马上就有人说了:“瞎说,一个要饭的,一个是导师,八竿子也打不着呀!”苕货娘说,那好办,我打电话问问就知道了。

    于是苕货娘在一圈人的注视下,拨通了电话:“喂,苕货,我问你一件事情哈……”

(选自《2015年中国小小说精选》)