下列实验方案不可行或结论不正确的是
A．用润湿的pH试纸测定饱和Na2CO3溶液pH
B．通过观察图中导管水柱的变化，验证铁钉生锈的原因主要是吸氧腐蚀
C．向Mg(OH)2悬浊液中滴加FeCl3溶液，出现红褐色沉淀，说明溶解度：Fe(OH)3＜Mg(OH)2
D．向同pH、同体积的醋酸和盐酸溶液中加入足量镁粉，通过完全反应后收集到的H2体积比较两种酸的电离程度：醋酸＜盐酸
答案：A
题目分析：润湿的pH试纸测定饱和Na2CO3溶液pH，溶液被稀释产生误差，A选项不正确，发生吸氧腐蚀，导管水柱上升，B选项正确，溶解度较小的Mg(OH)2会转化为溶解度更小的Fe(OH)3，C选项正确，同pH、同体积的醋酸和盐酸溶液中，醋酸中产生氢气多于盐酸，所以两种酸的电离程度：醋酸＜盐酸，D选项正确。
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| Can plants eat people? Probably not, but there are many plants that eat meat. Some of them are big, and they can eat small animals. One famous meat-eating plant is the Venus flytrap. The Venus flytrap is a very strange plant. It grows in dry parts of the United States. Its leaves are like the pages of a book. (A) They can open and close very quickly. Inside the leaves, there are three small hairs.If an insect touches one of the hairs, the leaf closes quickly. The insect cannot get out. In about half an hour, the leaf presses (挤压) the insect until it is dead. Then, the plant covers the insect with a special liquid (液体). Slowly, the plant eats the insect. (B) Plants are living things that have leaves and roots and grow in earth. Most of them get energy from the sun, the air, and the ground. In some places, the ground is very poor. It doesn't have all the important things that plants need, especially nitrogen (氮). Animal meat has a lot of nitrogen, so some plants eat meat to get what they need. Let's hope that some of the bigger plants don't get the same idea! |
| 1. Can plants get energy from the air? 2. Why is Venus flytrap a famous piant? 3. In some places, why do some plants get energy from animal meat? 4. 写出（A）处划线单词they所指代的名词。 5. 将（B）处划线句子改为两个简单句。 Plants are living things. |