Question

Pencils that are sharpenedfrom both sides can be used as electrodes. Can you tell why?

Answer 1

Pencils that are sharpenedfrom both sides can be used as electrodes because of graphite inside pencil which will be seen after sharpening

Answer 2

Pencils that are sharpened from both sides can be used as electrodes because, the graphite inside that pencil gets exposed from both ends and graphite is a good conductor of electricity.

To properly understand this answer, we have to know more about conductors of electricity.

Cnductors of electricity :

• The materials which provide low resistance against the electrical current flow through them, and hence conduct a significant amount of electrical through them, are know as (good) cnductors of electricity.
• Most of metals are good conductors of electricity. Also, some non-metals like graphite also conduct good amount of electricity.

An electrode should conduct electricity from its top end to its bottom end and finally to the electrolyte, for proper electrolysis.

Now, the graphite of the pencil is insulated with a wooden layer around it. When we sharpen the pencil the wooden layer is carved out and the inner graphite is exposed. Doing this at both ends, exposes graphite at both ends, which let the electricity to flow from top to the bottom end and finally to the electrolyte (because the bottom exposed end is in direct contact with the electrolyte).

Hence, we have discussed about the reason behind the usage of both end sharpened pencil as electrode.