There is a blackboard ________ our classroom. Our teacher was standing ________ the blackboard at this time yesterday. A. in front of; in the front of B. in the front of; on C. in the front of; in front of D. in front of; in 答案:C实验室中所用少量氯气是用下列方法制取的,4HCl(浓)+MnO2 △ . Cl2↑+MnCl2+2H2O试回答下列问题:(1)该反应是氧化还原反应吗?______,如果是氧化还原反应,请指出______是氧化剂,______是还原剂,______是氧化产物,______是还原产物,根据上述氧化还原反应式判断氧化性:______>______;还原性:______>______.(2)写出该反应的离子方程式______ (3)用双线桥法标出该反应电子转移的方向和数目______.