A:向氯化亚铁溶液中通入氯气:Fe2++Cl2═Fe3++2Cl﹣
B:将氯气通入冷的氢氧化钠溶液中:Cl2+2OH﹣═Cl﹣+ClO﹣+H2O
C:氨气通入醋酸溶液CH3COOH+NH3═CH3COONH4
D:金属铝溶于盐酸中:Al+2H+═Al3++H2↑
Dear Jenny,
Now we are in the hospital of our city . My mother and I have a bad cold . We sees many children here . Some people have a cold. Some people have a headache. Some people have a fever. They a re waiting outside the doctor's room .Now it's our turn.
Yours,
Jack
光电效应实验装置示意如图.用频率为ν的普通光源照射阴极K,没有发生光电效应.换用同样频率为ν的强激光照射阴极K,则发生了光电效应;此时,若加上反向电压U,即将阴极K接电源正极,阳极A接电源负极,在KA之间就形成了使光电子减速的电场,逐渐增大U,光电流会逐渐减小;当光电流恰好减小到零时,所加反向电压U可能是下列的(其中W为逸出功,h为普朗克常量,e为电子电量)( )