下列离子方程式书写正确的是
A．向NaHCO3溶液中加入足量的Ba(OH)2溶液
2HCO3- + Ba2+ + 2OH- = BaCO3↓ + CO32- + 2H2O
B．向石灰石中滴加稀硝酸
CaCO3 + 2H+ = Ca2+ + CO2↑ + H2O
C．用惰性电极电解KOH溶液时阴极电极反应
2H2O – 4e- = O2 + 4H+
D．NaOH溶液中通入少量硫化氢气体：2OH- + H2S = S2 - + 2H2O
BD
正确答案：BD
A、HCO3- + Ba2+ +OH- = BaCO3↓+H2O
B、正确；
C、不正确，阴极得电子，2H2O＋2e-=2OH―＋H2↑
D、正确。
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| There is a shop near my home. It 1 many things like bread, milk, 2 and drinks. My mother often goes shopping there 3 Sundays and buy food. I go with her, too, and carry baskets 4 her. The people in the shop are very friendly. They 5 us put the heavy things on the bikes. It doesn't sell 6 . I must buy rulers, pens and pencils in other shops. The shop is not open 7 eight o'clock in the morning, so don't go to buy things before 8 . It 9 at ten in the evening. Mother says we can go there 10 supper time. But I think it is too late. | ||||
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