问题
选择题
Tom asked the candy makers if they could make the chocolate easier ________ into small pieces.[ ]
A. break
B. breaking
C. broken
D. to break
答案
答案:D
Tom asked the candy makers if they could make the chocolate easier ________ into small pieces.[ ]
A. break
B. breaking
C. broken
D. to break
答案:D
有一白色固体混合物,可能含有的阴、阳离子分别是
阳离子 | K+ Ba2+ Ag+ Mg2+ NH4+ Na+ |
阴离子 | SO42- SO32- CO32- AlO2- |
(1)取该粉末,加水后得到无色溶液,且未嗅到气味;用pH试纸测得溶液的pH为12.由此可推出肯定不存在的离子是______.
(2)向溶液中滴加盐酸溶液,开始有沉淀生成,继续滴加,沉淀消失,同时有无色无味气体逸出.由此可推出肯定存在的离子是______,肯定不存在的离子是______.
(3)尚待检验的离子是______,其检验方法______.