Why is anode positive

This electrode can accept electrons from those negative ions or other species in the solution and hence behaves as an oxidizing agent. In any electrochemical cell the anode is the electrode at which oxidation occurs. An easy way to remember which electrode is which is that anode and oxidation begin with vowels while cathode and reduction begin with consonants. The following video shows this process taking place in a neutral solution of water with some electrolytes present.

As an example of how electrolysis can cause a chemical reaction to occur, suppose we pass a direct electrical current through 1 M HCl. Such a result is true of electrolysis in general: electrical current supplied from outside the system causes a non-spontaneous chemical reaction to occur. Although electrolysis always reverses a spontaneous redox reaction , the result of a given electrolysis may not always be the reaction we want.

In an aqueous solution, for example, there are always a great many water molecules in the vicinity of both the anode and cathode. These water molecules can donate electrons to the anode or accept electrons from the cathode just as anions or cations can.

Consequently, excess electrons from the cathode are accepted by water molecules instead:. A similar situation arises at the anode. The name diode was extended to semiconductor devices that had the same one-way current property of the existing diodes of the day, which were mostly vacuum tubes. The "di" in diode refers to 2. A "diode" was a 2-element tube, as apposed to a triode, pentode, and others. Wouter van Ooijen Wouter van Ooijen That's what I recall from my chemistry classes, too.

Also, I recall my favorite chemistry teacher saying: "If you know what you're doing, you may do anything. This will get you confused when looking at batteries. Show 5 more comments. Saqib Saqib 1. The Overflow Blog. Does ES6 make JavaScript frameworks obsolete? Podcast Do polyglots have an edge when it comes to mastering programming Featured on Meta.

Now live: A fully responsive profile. Linked 0. Related 1. Hot Network Questions. Both these terms can be defined by the flow of current. Thus, a cathode can be considered as an electrode from which the current exits a polarized electrical device.

In the same way, an anode can be described as an electrode from which the current enters into the polarized electrical device. The terms Cathode and Anode were finalized in by William Whewell. He has adapted the words from the Greek word named, kathodos , 'way down' or 'descent. The pictorial representation of both cathode and anode is given below. When we speak about the cathode in chemistry, it can be said to be the electrode where the reduction takes place.

In an electrochemical cell, this is common. Here, the cathode results negative due to the electrical energy that is supplied to the cell results in the decomposition of chemical compounds. However, it can also be said to be positive similar to the case of a galvanic cell where the chemical reaction tends to the generation of electrical energy.

Also, a cathode is said to be either a cold cathode or a hot cathode. A cathode that is heated in the presence of a filament to emit electrons using thermionic emission is called a hot cathode, whereas the cold cathodes are not heated with any filament.

In general, a cathode is flagged as "cold" if it emits more electrons than the ones generated by thermionic emission alone. In the most basic form, an anode in electrochemistry is defined as the point where an oxidation reaction takes place.

In general, at an anode, anions, or negative ions, due to its electrical potential, tend to react and give off the electrons.