问题 选择题

有关AgCl的沉淀溶解平衡的说法中,不正确的是(  )

A.AgCl难溶于水,溶液中没有Ag+和Cl-

B.升高温度时,AgCl的溶解度增大

C.向AgCl饱和溶液中,加入NaCl固体,会析出AgCl固体

D.达到沉淀溶解平衡时,AgCl沉淀生成和沉淀溶解不断进行,但速率相等

答案

A、AgCl难溶于水,但溶液中存在溶解平衡,饱和溶液中有Ag+和Cl-,故A错误;

B、温度升高增大氯化银的溶解度,故B正确;

C、沉淀溶解平衡状态存在溶度积常数,随温度变化,加入氯化钠,增大氯离子浓度平衡沉淀方向进行,生成氯化银沉淀,故C正确;

D、氯化银在水中难溶形成饱和溶液,存在沉淀溶解平衡,是动态平衡,沉淀溶解速率相等,故D正确;

故选A.

阅读理解

One midnight, a little girl woke up to get water. She got up and down her bed by herself, walked to the bedroom door and opened it. She looked outside and walked back, for it was so dark in the living room that she feared. Her mother told her not to be afraid and take courage.

“ What is courage? Do you have courage?” She asked, running to her mother’s bed. “ Courage is the brave breath(气). I have it.” Her mother answered. The girl held out her little hands and asked her mother to give her. After her mother blew out two mouthfuls of breath into her little cold hands, the little girl clenched her fists(握拳)nervousely, afraid that the “breath of courage” would run away. Then with her fists clenched, she walked out of the bedroom towards the bathroom with nothing to fear.

Her mother said to herself, “ It’ll be nice if someone can blow some kind of breath to me. Then I can hold it in my hands too when I feel terrified or lost.

In fact, mostly, what we are terrified of is nothing but the fear in our mind. Who we should deal with is nobody but ourselves.

小题1:The girl walked back because______.

A.the bedroom door was locked.

B.She wasn’t thirsty anymore

C.her mother wouldn’t go with her

D.She was too afraid of the dark小题2:To stop “mother’s breath ”from running away, the girl______.

A.clenched her fists

B.held her own breath

C.held out her little hands

D.talk to her mother小题3:The writer mainly wants to tell us that______.

A.children learn to be brave quickly.

B.the fear in one’s mind is the real problem.

C.adults are always brave enough.

D.the mother can deal with anything with breath.

单项选择题