题干

25℃时,水中存在平衡:H2O⇌H++OH△H>0,下列叙述正确的是(   )

A:加入稀氨水,平衡逆向移动,c(OH)降低,Kw不变

B:加入少量固体CuSO4,c (H+)增大,Kw不变

C:加入少量固体CH3COONa,平衡逆向移动,c (H+)降低,Kw不变

D:加热到90℃,Kw增大,溶液仍呈中性,pH不变

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答案(点此获取答案解析)

B

同类题2

阅读理解

    On a hot summer day, my friend Kathy and I drove slowly towards Indiana to our friend's house. After two hours' driving, we stopped before a parking lot to order coffee there. “It's my treat,” I said, trying to find my purse in the back seat, but it wasn't there. I knew it could easily slip under a seat, so I searched around. But nothing was found. At last I remembered I had left my purse on the roof of the car, in the Dunkin' Donuts parking lot. I panicked and was sure that my credit cards had already gone. But something told me to call the Dunkin' Donuts just in case.

     “Oh thank goodness,” the clerk said when I called. “We were going through your purse, trying to find a way to get in touch with you. Someone found your purse lying in the parking lot and turned it in.” Refusing any kind of reward, the shop owner express-mailed it to our friend's home.

    A few years later, on a snowy Minnesota winter night, my car suddenly broke down and I had to walk home. Before leaving my car, I remembered my purse was still in my pocket. But when I got home, it wasn't there. I searched again around the seats but my purse didn't appear. Had I lost my purse again? Knowing my good fortune might not repeat itself, I called the credit card company and my bank to freeze my accounts.

    But the next morning I got a call. “Is this Heidi Grosch? We found your purse lying on the ground.” Again, everything was there and the finder refused to accept any payment.

    I will always be grateful to those who are kind to restore my purse.