What is secondary reference electrode?
In general, secondary reference electrodes are electrodes of the second kind, i.e. metal electrodes coupled to a solubility equilibrium of a salt of this metal and an electrolyte solution containing a fixed concentration of the anion of the sparingly soluble metal salt.
What are secondary reference electrodes explain the construction of calomel electrode with a neat diagram and reactions?
The calomel electrode is widely used as a secondary reference electrode. a paste of Hg and Hg2Cl2 (mercurous chloride, i.e., the calomel and saturated KCl solution so as to fill the vessel and the arm C as shown in figure. (2) The potential developed on this electrode depends upon the concentration of chloride ions.
What are various types of reference electrodes?
Several types of reference electrodes exist.
- Silver/Silver Chloride Reference Electrodes.
- Calomel Reference Electrodes.
- Hydrogen Reference Electrodes.
- Double Junction Reference Electrodes.
- Liquid Junction Reference Electrodes.
What are the major requirements of a reference electrode enumerate?
Reference electrode
- Platinized platinum electrode,
- Hydrogen gas,
- Acid solution with an activity of H+ = 1 mol/L,
- Hydroseal for prevention of oxygen interference,
- Reservoir via which the second half-element of the galvanic cell should be attached.
What is secondary electrode give two examples for secondary electrode?
Such electrodes are known as secondary standard electrodes. Two such electrodes arc: Calomel Electrodes. Silver Electrodes.
Which electrode is used as secondary electrode?
Explanation: Mercury chloride is known as calomel. The most important general purpose secondary electrode is calomel electrode.
What are reference electrodes explain the construction and working of calomel electrode?
Calomel electrode is the mercury-mercurous chloride electrode. It consists of a glass vessel having a bent side tube. A platinum wire sealed into a glass tube is dipped into mercury layer is used to provide the external electrical contact. The side tube is used for making electrical contact with a salt bridge.
Why is calomel electrode used as reference electrode?
Some examples of reference cells include: Calomel electrode: This reference electrode consists of a mercury and mercury-chloride molecules. This electrode can be relatively easier to make and maintain compared to the SHE.
What is the role of reference electrode?
The purpose of the reference electrode is to provide a stable potential for controlled regulation of the working electrode potential and in doing so allow the measurement of the potential at the working electrode without passing current through it.
What is the example of secondary reference electrode?
However, this electrode is impractical in routine usages, thus secondary reference electrodes, such as calomel, sulphate, and silver/silver chloride (Ag/AgCl) are used [80]. The potential developed is determined by the chloride concentration of the inner solution, as defined by the Nernst equation.
What is a secondary reference electrode?
Secondary reference electrode: The electrode whose potential is determined by connecting to the standard hydrogen electrode is called a secondary reference electrode. What is Electrode Potential?
Why is calomel used as a secondary reference electrode?
However, this electrode is impractical in routine usages, thus secondary reference electrodes, such as calomel, sulphate, and silver/silver chloride (Ag/AgCl) are used [ 80 ]. As a secondary reference electrode, the Ag/AgCl electrode is the most common due to its simplicity, stability, and capability of miniaturization.
What is the standard potential of a hydrogen electrode?
The standard potential of the hydrogen electrode is conventionally set to zero at all temperatures, thus establishing a hydrogen scale of standard potential. However, this electrode is impractical in routine usages, thus secondary reference electrodes, such as calomel, sulphate, and silver/silver chloride (Ag/AgCl) are used [ 80 ].
What is the construction of a mercury electrode?
Construction : The electrode consists of a glass tube provided with a bent side tube and another side tube B. A little H g is placed at the bottom of the dry glass tube. A rubber bung carrying a thin glass tube with a platinum wire is then inserted, taking care that the platinum wire drips into mercury.