设NA为阿佛德罗常数，下列叙述中不正确的是（ ）
A．46gNO2和N2O4混合气体中含有原子数为3NA
B．1L1mol/L醋酸溶液中离子总数为NA
C．1molMg与足量O2或N2反应均失去2NA个电子
D．标准状况下22.4LH2含有NA个分子
A.46gNO2和N2O4混合气体相当于21molNO2，含3mol原子，故正确；
B．醋酸电离程度很小，1L1mol/L醋酸溶液中离子总数应小于1mol，故错误；
C．镁在化合物中显+2价，故正确；
D．氢气是气体，标准状况下22.4LH2是1mol，故正确．
故选B．
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| It was Sunday yesterday. Henry wasn't 1 home. He was on a 2 to the zoo. An old man got on the bus. Henry stood up and 3 to him, "Come and sit here, please." He helped the old man 4 ." Thanks 5 , good boy," the old man said."You're welcome," said Henry. The bus went on. Thirty minutes later, it stopped 6 the zoo. Henry got off the bus and said 7 to the old man. The old man smiled (微笑) at him in a friendly way. Henry went into the zoo. 8 of the people there are students. He 9 a lot of animals and birds, and he also took many photos. He spent a happy weekend 10 he helped others and had a good time in the zoo. | |||
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