What is electrocapillary phenomenon?
Electrocapillarity (or electrocapillary phenomena) are the phenomena related to the thermodynamics of charged interfaces, especially to changes in the interfacial energy (interfacial stress or tension) as the electrode potential or the composition (concentration) of the electrolyte solution changes.
What are electrocapillary curves?
Electrocapillary curves (surface tension γ as a function of the electrode potential E) for a series of room-temperature ionic liquids (RTILs) were measured using a mercury dropping electrode with the drop-weight (drop-volume) technique. The potential of zero charge is within a relatively narrow range.
Why dropping mercury electrode is used in polarography?
In polarography, mercury is used as a working electrode, because mercury is a liquid metal and thus the electrode can be renewed after each droplet. The working electrode is often a drop suspended from the end of a capillary tube.
What is the effect of concentration of electrolyte on the thickness of electric double layer?
The thickness of the diffuse region of the electric double layer depends on the concentration of ions in the solution: the lower the ion concentration, the thicker the diffuse layer.
What is the principle of dropping mercury electrode?
The principle consisted in weighing drops of mercury falling out of a thick-walled glass capillary into a solution. The dropping mercury, connected to a source of d.c.voltage, served as one electrode, the second electrode being the layer of mercury collecting at the bottom of the vessel.
How does a dropping mercury electrode work?
Dropping mercury electrode (DME) is a working electrode arrangement for polarography in which mercury continuously drops from a reservoir through a capillary tube (internal diameter 0.03 – 0.05 mm) into the solution. The optimum interval between drops for most analyses is between 1 and 5 s.
What changes occurs in electrical double layer by addition of electrolyte?
In the electrical double layer surrounding a particle suspended in an electrolyte solution, a layer of ions is attracted to the surface of the particle due to chemical and electrochemical reactions.
What is the thickness of double layer?
It is reciprocally proportional to the square root of the ion concentration C. In aqueous solutions it is typically on the scale of a few nanometers and the thickness decreases with increasing concentration of the electrolyte. The electric field strength inside the DL can be anywhere from zero to over 109 V/m.
Why do we drop mercury electrode in polarography?
The dropping mercury electrode (DME) is a working electrode made of mercury and used in polarography. Like other working electrodes these electrodes are used in electrochemical studies using three electrode systems when investigating reaction mechanisms related to redox chemistry among other chemical phenomena.
What is the advantage of dropping mercury electrode?
A major advantage of the DME is that each drop has a smooth and uncontaminated surface free from any adsorbed analyte or impurity. The self-renewing electrode does not need to be cleaned or polished like a solid electrode. This advantage comes at the cost of a working electrode with a constantly changing surface area.