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在普通化学演示实验中,有一类实验是电解、电镀等电化学反应。这些在电极上发生的现象,如在电极上析出气泡;金属从电极上溶解下来:以及电极上沉积出金属等,在课堂上演示时是很难用肉眼看清的,必须通过投影技术来解决。以下介绍用投影装置演示“铅的电沉积”的方法: 以金属铅为阴极和阳极,以硝酸铅溶液为电解液,把阴极与直流电源的正极相连;阳极与电源的负极相连,则阴极发生以下反应: Pb~2+2e=Pb 阳极发生以下反应:
In general chemistry demonstration experiments, there is a class of experiments that are electrochemical reactions such as electrolysis and electroplating. These phenomena occurring at the electrode, such as the precipitation of bubbles on the electrodes; the dissolution of the metal from the electrodes and the deposition of metal on the electrodes, are difficult to see with the naked eye during the demonstration in the classroom and must be resolved through projection techniques. . The following describes the method of demonstrating “lead electrodeposition” using a projection device: Using lead metal as the cathode and anode, using lead nitrate solution as the electrolyte, connecting the cathode to the positive electrode of the DC power supply; the anode is connected to the negative electrode of the power source, and the cathode is generated. The following reaction: Pb~2+2e=Pb The following reactions occur at the anode: