题干

三室式电渗析法处理含Na2SO4废水的原理如图所示,采用惰性电极,ab、cd均为离子交换膜,在直流电场的作用下,两膜中间的Na+和SO42﹣可通过离子交换膜,而两端隔室中离子被阻挡不能进入中间隔室.下列叙述正确的是(   )

A:通电后中间隔室的SO42﹣离子向正极迁移,正极区溶液pH增大

B:该法在处理含Na2SO4废水时可以得到NaOH和H2SO4产品

C:负极反应为2H2O﹣4e﹣=O2+4H+,负极区溶液pH降低

D:当电路中通过1mol电子的电量时,会有0.5mol的O2生成

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答案(点此获取答案解析)

B

同类题1

I was just outof college, only three days into a graduate (研究生)year in England,and I was pulling a heavy bag and suitcase(箱子)through the London Underground. I was also crying out of control.

   The day before yesterday, my uncle told me never to speak to him, his wife, or my two cousins again. Earlier,  I made a joke. I didn't mean to hurt my aunt's feelings, but it did.I spent the evening in an ugly blue telephone booth (电话亭). crying as I spoke to a family friend who lived in England.

   When I left the phone booth, I went back to a silent house with three closed bedroom doors. In the morning, I heard everyone get up and leave for work and school. I wrote a note to say sorry and pulled my bags to the train station. When I got into London, I had to take the underground to Angel Station to get to my family friend's house.

    I was familiar with the underground, but at the time, it was just endless white tiles(瓷砖).Coming to England seemed like a bad decision. Crying yet again, I tried to lift my suitcase up the stairs.

   When I was trying hard to walk forward, there were hands. Each time I faced another group of steps,a hand would lift the suitcase. At the top of the steps, the hand would let go, and I'd pull the suitcase to the next group. And just as I wanted to try again,another hand would appear.

   It happenedseveral times. I never looked up, because I couldn't stop crying.Each hand looked different, and many different people helped me, without asking or saying anything. I couldn't look up. I wasn't able to say thank you.

   I went on to have anamazing year studying in England, but that was the last time I saw or spoke to any of my uncle's family. Yet when I think about that terrible loss in 2008, I remember those strangers' hands. They were there when I needed them, and even now, they help me out of the sadness of that memory. I think of them as I ride the underground in Washington D. C. today, and I watch the citizens and tourists to offer hands at any time.