Question

What is the electrochemical equivalent law?

Answer 1

The electrochemical equivalent law relates the amount of a substance that is deposited or liberated during electrolysis to the quantity of electric charge passed through the electrolyte.

In simpler terms, it helps us understand how much material (like metal) is deposited at the electrodes when electric current flows through a solution.

Key points of the law:

1. Electrochemical Equivalent (Z): This is the mass of a substance deposited or dissolved when one coulomb of charge passes through the electrolyte. It’s expressed in grams per coulomb (g/C).
   

1. Mathematical Expression:
   

   \[
   m = Z \cdot Q
   \]
   Where:
   - \( m \) = mass of the substance deposited (in grams),
   - \( Z \) = electrochemical equivalent of the substance (in grams per coulomb),
   - \( Q \) = total charge passed (in coulombs).

1. Relationship with Faraday's Laws of Electrolysis: The electrochemical equivalent can also be derived from Faraday's laws. According to Faraday, the amount of substance deposited is proportional to the charge passed through the electrolyte. The electrochemical equivalent \( Z \) is given by:
   

   \[
   Z = \frac{M}{nF}
   \]
   Where:
   - \( M \) = molar mass of the substance (in grams per mole),
   - \( n \) = number of electrons involved in the reaction (valency),
   - \( F \) = Faraday's constant (96,485 C/mol).

Example:

If you want to know how much copper is deposited in an electroplating process, you can use the electrochemical equivalent law to find the mass of copper deposited when a certain amount of charge passes through the solution.

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In simple terms: The electrochemical equivalent law helps you calculate how much material will be deposited or dissolved when electric current flows through a solution. The more charge you pass, the more substance you get!