Question

What is electrochemistry? What are redox reactions? Explain the difference between a galvanic and an electrolytic cell.

Short answer

Electrochemistry is the study of chemical reactions involving electron transfer, usually in redox reactions. Redox reactions are chemical reactions where oxidation states change due to electron transfer, with one species being reduced and the other being oxidized. A galvanic cell converts chemical energy into electrical energy through a spontaneous redox reaction, whereas an electrolytic cell uses electrical energy to drive a non-spontaneous redox reaction, like in electrolysis or electroplating. The key differences are energy conversion, spontaneity, direction of electron flow, and applications.

Step-by-step solution

Define Electrochemistry

Electrochemistry is a branch of chemistry that deals with the study of chemical reactions involving the transfer of electrons between different chemical species, usually in the form of a redox reaction. It encompasses the processes and technologies in which the interconversion of electrical energy and chemical energy takes place, such as batteries and electrolysis.

Define Redox Reactions

Redox reactions, short for reduction-oxidation reactions, are chemical reactions where the oxidation states of the elements involved change due to the transfer of electrons. In a redox reaction, one element or species is reduced (gains electrons) while the other is oxidized (loses electrons).

Explain Galvanic Cells

A galvanic cell, also known as a voltaic cell, is an electrochemical cell that converts the chemical energy produced by a spontaneous redox reaction (meaning it occurs naturally, without any external input) into electrical energy. In a galvanic cell, the reactants are two different metals or metal ions, each in contact with an electrolyte solution. The two reactants form a redox pair, and the electrons flow from the more oxidized species (anode) to the less oxidized species (cathode) through an external circuit, generating electrical current.

Explain Electrolytic Cells

An electrolytic cell is an electrochemical cell where electrical energy is used to drive a non-spontaneous redox reaction (meaning it does not occur naturally and requires an external energy source). In an electrolytic cell, an external voltage source (a battery or a power supply) forces the electrons to flow in the opposite direction of the natural redox reaction. Electrolysis is the most common application of electrolytic cells, and it is used to split compounds into their constituent elements or to plate one metal onto another.

Highlight the Differences between Galvanic and Electrolytic Cells

The main differences between galvanic and electrolytic cells are as follows: 1. Energy Conversion: A galvanic cell converts chemical energy into electrical energy, while an electrolytic cell converts electrical energy into chemical energy. 2. Spontaneity: Redox reactions in galvanic cells are spontaneous, while those in electrolytic cells are non-spontaneous and need an external energy source to occur. 3. Direction of Electron Flow: In a galvanic cell, electrons flow from the anode to the cathode (in a direction that is favourable for the redox reaction), while in an electrolytic cell, they flow in the opposite direction (forced from the cathode to the anode). 4. Applications: Galvanic cells are used in batteries and other energy storage devices, while electrolytic cells are applied in processes like electrolysis and electroplating.