What is the Difference Between Photochemical and Electrochemical Reaction?

The main difference between photochemical and electrochemical reactions lies in the source of energy that initiates the reactions. Here are the key distinctions between the two types of reactions:

Photochemical Reactions:

1. Occur due to the absorption of light energy (photons).
2. Initiated by the absorption of sunlight, such as in photosynthesis.
3. Example: Photosynthesis, where CO2, H2O, and sunlight are converted into glucose and oxygen.

Electrochemical Reactions:

1. Occur due to the absorption of electrical energy.
2. Accompanied by the passage of an electric current.
3. Example: Electrolysis of water, where water (H2O) is decomposed into hydrogen gas (H2) and oxygen gas (O2) using an electric current.

In summary, photochemical reactions are initiated by the absorption of light energy, while electrochemical reactions are initiated by the absorption of electrical energy.

Comparative Table: Photochemical vs Electrochemical Reaction

Here is a table comparing photochemical and electrochemical reactions:

Photochemical reactions are initiated by the absorption of energy in the form of light, leading to the creation of transient excited states whose properties differ from the initial state of the molecule. Electrochemical reactions, on the other hand, involve the transfer of electrons between two substances, typically a solid electrode and an electrolyte, and are accompanied by the passage of an electric current.