铬（Cr）与铝的性质相似，如Cr（OH）3+OH—→CrO2—+2H2O，下列推断中错误的是
A．往CrCl3溶液加入过量NaOH溶液不可制得Cr（OH）3
B．对CrCl3·6H2O加热脱水可得CrCl3
C．Cr2O3既能溶于盐酸，又能溶于氢氧化钠溶液
D．CrO2—水解使溶液显碱性
答案：B
题目分析：A． Cr（OH）3有两性，能被过量的强碱溶解，因此往CrCl3溶液加入过量NaOH溶液不可制得Cr（OH）3。正确。B．CrCl3是强碱弱酸盐，对CrCl3·6H2O加热脱水时发生水解反应产生氢氧化铬和氯化氢，氯化氢随着水分的蒸发而挥发所以减弱得到固体是Cr（OH）3。错误。C．Cr2O3是两性氧化物，既能溶于盐酸，又能溶于氢氧化钠溶液。正确。D．CrO2—水解时发生反应：CrO2—+2H2O 
Cr（OH）3+OH-。故使溶液显碱性。正确。
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| One night I decided to spend some time building a happier and closer relationship with my daughter. For several weeks she had been 1 me to play chess with her, so I suggested a game and she eagerly 2 . It was a school night, however, and at nine o'clock my daughter asked if I could 3 my moves, because she 4 to go to bed; she had to get up at six in the morning. I 5 she had strict sleeping habits, 6 I thought she ought to be able to 7 some of this strictness. I said to her, " 8 , you can stay up late for once. We're having 9 ." We played on for another fifteen minutes, during which time she looked 10 . Finally she said, "Please, Daddy, do it quickly." "No," I replied. "If you're going to play it 11 , you're going to play it slowly." And so we 12 for another ten minutes, until 13 my daughter burst into tears, and 14 that she was beaten. Clearly I had made 15 . I had started the evening wanting to have a 16 time with my daughter but had 17 my desire to win to become more 18 than my relationship with my daughter. When I wa s a child, my desire to win 19 me well. As a parent, I 20 that it got in my way. So I had to change. | ||||
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