问题 问答题

有一瓶溶液,可能含有Na+、Ba2+、H+、Cl-、CO32-、SO42-、OH-中的几种,进行如下实验:

①取试样溶液,装入试管,加入BaCl2试液,溶液中产生白色沉淀,过滤.

②在滤液中滴入酚酞试液,溶液呈红色.

③在沉淀中加入稀硝酸,白色沉淀全部溶解,并产生气泡.

请回答下列问题:

(1)该溶液中一定含有的离子是______;该溶液中一定不含有的离子是______.

(2)步骤③沉淀溶解的化学方程式是______.

(3)该溶液中可能含有的离子是______,要证明溶液中是否含有该离子.请回答下列实验的操作、现象、结论.另取试样溶液,为排除溶液中的______离子对实验的干扰,先加入足量的______,再滴入______溶液,若有现象:______产生,证明溶液中含有该离子;否则证明溶液中不含有该离子.

答案

(1)加入BaCl2试液,溶液中产生白色沉淀,说明该沉淀是碳酸钡白色沉淀或硫酸钡白色沉淀或都有;沉淀中加入稀硝酸,白色沉淀全部溶解,并产生气泡,说明只是碳酸钡沉淀;说明溶液中一定含有CO32-则一定不含有Ba2+、SO42-,②中在滤液中滴入酚酞试液,溶液呈红色说明溶液中含有OH-.则溶液中一定不含有H+;CO32-、OH-都为阴离子,溶液中必须有阳离子,故一定含有Na+

故答案为:Na+、CO32-、OH-;Ba2+、H+、SO42-

(2)沉淀为BaCO3沉淀,故是碳酸钡和硝酸反应;故答案为:BaCO3+2HNO3═Ba(NO32+H2O+CO2

(3)①、②、③中对氯离子无法鉴定,鉴定氯离子需用硝酸银溶液,因Ag+与CO32-和OH-也能反应生成沉淀,所以需加入稀硝酸除去CO32-和OH-然后再滴加硝酸银若有白色沉淀则含有氯离子;

故答案为:Cl-;CO32-和OH-;稀硝酸;AgNO3;白色沉淀

多项选择题
填空题



The Commission is expected to propose allowing people to choose which legal jurisdiction they would come under, based on their (1) or their residency. But the proposal is set to (2) because of the very different laws on divorce that apply across the EU. The Commission wants to (3) problems over which law to apply when, for example, a married couple from one member state is (4) in another member state or when the couple is of different EU nationalities.
The (5) of member states are said to be (6) the idea and responded positively to a (6) which followed the (8) of a Commission Green Paper. With 15 percent of German divorces each year involving couples of different nationalities, the government of Berlin (9) see resolved the issue of which laws should apply.
But some member states are expected to resist the (10) which would involve allowing different divorce laws to be applied in their countries. For example, in Ireland where the divorce law states a couple must have been separated for four years, establish that their marriage has broken down and be offered (11) , a couple from Sweden could apply to an Irish court to allow them to divorce under Swedish law, where divorce can be (12) quickly.
The Irish government’s (13) to the Commission on the Green Paper stated: "Ireland is not in favor of allowing (14) to choose the applicable law, as this could be open to abuse.., such abuse would be likely to (15) most on divorce regimes, such as that of Ireland, which require a relatively long separation period." Ireland, like the UK, however, is allowed to choose whether to "opt-in" to such a proposal under rules agreed in the Amsterdam treaty. Malta has no such (16) but could (17) the proposal in the Council of Ministers since (18) approval will be required.
"It is going to lead to (19) ," said Geoffrey Shannon, Irish expert on the Commission on European Family Law, which examines the (20) of EU family law.
The proposal would also mean that judges would have to be trained in the divorce law of all 25 member states.