Difference between positive and negative electrodes and positive and negative electrodes

The answer to the difference between positive and negative poles is as follows:

1.

The positive electrode refers to a pole of current output, that is, a pole of electronic input; On the contrary, the negative electrode is a pole of current input and electron output; For primary cells, the cathode and anode are the same, and so are the anode and cathode, but for electrolytic cells, the opposite is true.

In fact, it is well understood that for a reaction, whether it takes place in an electrolytic cell or a galvanic cell, the cathode and anode are fixed, but the anode and cathode can be changed, because their definitions are related to the direction of current, and the change of current direction determines that the anode and cathode can be changed. The current direction of primary battery and electrolytic cell is opposite.

2. Introduction of electrodes

A component in an electronic or electrical device or equipment used as two terminals for inputting or outputting current in a conductive medium (solid, gas, vacuum or electrolyte solution). One pole of the input current is called anode or positive pole, and the other pole of the output current is called cathode or negative pole. There are various types of electrodes, such as cathode, anode, welding electrode and electric furnace electrode.

In the battery, the electrode generally refers to the position where the redox reaction occurs with the electrolyte. There are positive and negative electrodes. Generally, the positive electrode is the cathode, which gains electrons and carries out the reduction reaction, while the negative electrode is the anode, which loses electrons and carries out the oxidation reaction. Electrodes can be metallic or nonmetallic. As long as they can exchange electrons with electrolyte solutions, they become electrodes.

name

The naming methods are very complicated, and some of them are named according to the metal parts of electrodes, such as copper electrodes and platinum electrodes. Some of them are named according to the characteristic substances in the active redox pair of electrodes, such as calomel electrode and hydrogen electrode; Some are named according to the shape of the metal part of the electrode, such as mercury dropping electrode and turntable electrode; Some are named after the function of the electrode. These names such as reference electrode and sodium ion selective electrode (see ion selective electrode) are all valid.

4. Representation symbols

Normally, the battery will be marked with "+"symbol, which is the positive electrode, and the other end will be marked with "-"symbol, which is the negative electrode. At the same time, only the positive electrode has a "+"on the battery, and the negative electrode does not. Color can also represent positive and negative poles: red represents positive pole and black represents negative pole.