下列反应的离子方程式正确的是（ ）
A．NaHCO3溶液与醋酸：CO32-+2CH3COOH=2CH3COO-+H2O+CO2↑
B．硝酸银溶液与铜：Cu+Ag+=Cu2++Ag
C．用醋酸除水垢：2CH3COOH+CaCO3=Ca2++2CH3COO-+H2O+CO2↑
D．向NaHSO4溶液中加入Ba（OH）2溶液至呈中性：H++SO42-+Ba2++OH-=H2O+BaSO4↓
A、NaHCO3溶液与醋酸：HCO3-+CH3COOH=CH3COO-+H2O+CO2↑，故A错误；
B、硝酸银溶液与铜反应的离子方程式为：Cu+2Ag+=Cu2++2Ag，故B错误；
C、用醋酸除水垢反应的离子方程式为：2CH3COOH+CaCO3=Ca2++2CH3COO-+H2O+CO2↑，故C正确；
D、向NaHSO4溶液中加入Ba（OH）2溶液至呈中性，硫酸氢钠和氢氧化钡按2：1恰好反应；反应的离子方程式为：2H++SO42-+Ba2++2OH-=2H2O+BaSO4↓，故D错误；
故选C．
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| Each of us makes mistakes from time to time. In fact, we can 1 a lot from our mistakes. Donnie was a 2 student and never answered questions in class. He was 3 to make mistakes. He never finished his homework 4 he didn't want to make any mistakes. Nothing changed 5 Marry Anne, a teacher, came to our 6 . One morning, Marry Anne asked Donnie to 7 some questions. After a while Donnie was in tears because he made a mistake. 8 Marry Anne got a box full of erasers from the desk. "Look, Donnie," she said standing 9 him."I've got something to show you." She 10 the erasers, one at a time, and put them on the desk. "See these erasers, Donnie?" she continued."Do you know 11 the erasers become smaller and smaller? That's because we make mistakes. But we erase the mistakes and try 12 . That's what you must learn." "Here," she said,"I'll 13 one eraser on your desk, so you will remember that 14 may make mistakes." Donnie looked at Marry Anne and smiled. Donnie 15 a lot from then on. He knew that everyone had the permission to make mistakes as long as you learned them and tried again. | ||||
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