Question

Define the following terms with examples: (i) Electrolysis (ii) Electrolytic cell (iii) Electrochemical cell (iv) Ions and electrodes (v) 1 faraday

Short answer

Question: Define the following electrochemistry terms and provide an example for each: (i) Electrolysis, (ii) Electrolytic cell, (iii) Electrochemical cell, (iv) Ions and electrodes, and (v) 1 faraday. Answer: (i) Electrolysis is a process in which an electric current is passed through an electrolyte to induce a non-spontaneous redox reaction, such as the decomposition of water into hydrogen and oxygen gases. (ii) An electrolytic cell is an apparatus using an external electrical source to drive a non-spontaneous electrochemical reaction, like the electrolysis of molten sodium chloride to produce sodium metal and chlorine gas. (iii) An electrochemical cell converts chemical energy into electrical energy through spontaneous redox reactions, for example, the Daniell cell. (iv) Ions are charged particles, while electrodes are conductive materials facilitating electron transfer in an electrochemical process, as seen in the electrolysis of copper sulfate. (v) 1 faraday is a unit of electrical charge equal to the charge carried by one mole of electrons, approximately 96,485 coulombs, used in electrochemistry calculations like determining the amount of substance produced during electrolysis.

Step-by-step solution

(i) Electrolysis

Electrolysis is a process in which an electric current is passed through an electrolyte to induce a non-spontaneous redox reaction. In this process, chemical bonds in the electrolyte are broken, and new bonds are formed at the electrodes through the movement of ions between the cathode and anode. An example of electrolysis is the decomposition of water into hydrogen and oxygen gases.

(ii) Electrolytic cell

An electrolytic cell is an apparatus that uses an external electrical source to drive a non-spontaneous electrochemical reaction. It consists of two electrodes (cathode and anode) dipped in an electrolyte solution. The electrons transfer from the anode (negative electrode) to the cathode (positive electrode) during electrolysis. A common example of an electrolytic cell is the electrolysis of molten sodium chloride to produce sodium metal and chlorine gas.

(iii) Electrochemical cell

An electrochemical cell is a device that converts chemical energy into electrical energy through spontaneous redox reactions. It consists of two half-cells, each containing a redox species and an electrode that are connected through a salt bridge and an external circuit. An example of an electrochemical cell is the Daniell cell, which consists of a zinc anode, a copper cathode, and an electrolyte solution of zinc sulfate and copper sulfate.

(iv) Ions and electrodes

Ions are charged particles formed when an atom gains or loses one or more electrons. In an electrochemical process, ions move between the cathode and anode within an electrolyte solution. Electrodes are conductive materials, such as metal, that serve as a site for electron transfer in an electrochemical process. The cathode is the electrode where reduction (gain of electrons) occurs, and the anode is the electrode where oxidation (loss of electrons) occurs. An example of ions and electrodes can be observed in the electrolysis of copper sulfate, where copper ions (Cu^2+) are reduced at the cathode to form copper metal, while in the anode, the sulfate ions may react with water to produce oxygen gas and sulfuric acid.

(v) 1 faraday

A Faraday, named after scientist Michael Faraday, is a unit of electrical charge, which is equal to the charge carried by one mole of electrons. 1 faraday (1 F) is approximately 96,485 coulombs (C). It is often used in electrochemistry calculations, such as determining the amount of substance produced during electrolysis. For example, during the electrolysis of copper sulfate, the deposition of one mole of copper metal at the cathode requires 2 faradays of charge, as Cu^2+ ions gain two electrons to form Cu(s).