A:稀硫酸滴在铜片上:Cu + 2H+ ='==' Cu2+ + H2 ↑
B:氧化铁与硫酸反应:O2- + 2 H+ ='==' H2O
C:硫酸钠和氯化钡两种溶液混合:Ba2++SO42- ='==' BaSO4 ↓
D:盐酸与石灰石反应:CO32- + 2H+ ='==' H2O + CO2 ↑
在地图上不能作为确定方向依据的是( )
- Excuse me, can you tell me the way to the Summer Palace?
- ___________.You can ask the policeman over there.