Why We Use Ag AgCl as reference electrode?

Why We Use Ag AgCl as reference electrode?

Silver/silver chloride is a common choice of biological electrodes due to its low half-cell potential of about +222 mV (SHE), low impedance, with a toxicity lower than that of the calomel electrode containing mercury.

Is Ag AgCl a reference electrode?

Silver/Silver Chloride (Ag/AgCl) – The Ag/AgCl reference electrode is simpler in construction than the SCE and it contains no mercury. It is a very stable reference electrode. Mercury/Mercurous Sulfate Reference Electrode (Hg/Hg2SO4) – The Hg/HgSO4 reference electrode uses a filling solution of potassium sulfate.

How do you make an AgCl reference electrode?

Clean the silver wire with a fine grade emery paper and rinse it with distilled water. Insert the part to be coated into 0.1 M HCl and pass 10 mA/cm2 for about 1 min, using a platinum wire as a cathode. During the electrolysis a black deposit is formed on the silver.

How do you make Ag AgCl wire?

A silver wire (1.0 mm in diameter) was used to prepare an Ag/AgCl electrode. The wire was cut to 10 cm long, polished and cleaned before immerging it about 6.5-7.0 cm into a solution of 0.5M FeCl3 for 12 h, to form a AgCl film on the silver wire. The electrode was then washed with water and used as a working electrode.

How does a Ag AgCl reference electrode work?

Ag/AgCl is a second type electrode in which the metal is in contact wit its low soluble salt and the anion of that salt. In your case, the metal is Ag in contact with its low soluble salt AgCl + its anion Cl(-) and the reaction is AgCl + e = Ag + Cl(-). This reaction is the half cell of Ag/AgCl ref.

What is the advantage of Ag AgCl electrode over calomel electrode?

Although Ag/AgCl is not the best reference electrode, but it is more convenient than, for example Calomel, because it can be use as a thin wire which can be placed anywhere in the system without taking a space.

How do you test an AgCl reference electrode?

Dip your made Ag/AgCl reference electrode and additional reference electrode of the same type (or a calomel reference electrode) in a small beaker containing 3 M NaCl. Connect both the electrodes to voltmeter. Read the potential difference between the electrodes on the voltmeter.

What is Ag AgCl electrode?

Silver/Silver Chloride (Ag/AgCl) The silver/silver chloride reference electrode is composed of a silver wire, sometimes coated with a layer of solid silver chloride, immersed in a solution that is saturated with potassium chloride and silver chloride.

How do you keep Ag AgCl reference electrode?

Storage. Both Ag/AgCl and SCE reference electrodes should be stored in just slightly less than saturated KCl solution. Keeping the solution just below saturation allows enough ionic flow to prevent salt crystals from forming in the glass pores.

How do you convert AgCl to rhe?

1. The general equation for this conversion at any pH using Ag/AgCl reference electrode is:
2. E(RHE) = EAg/AgCl + 0.059 pH + EoAg/AgCl.
3. Where EoAg/AgCl = 0.1976 V at 25oC and E Ag/AgCl is your working potential.

Why Ag AgCl is used as a reference electrode not NaCl KCl?

Saturated solutions of KCl or NaCl are used because the concentration is reproducible even if the temperature changes (if solid salt is present) and are immune to the effects of water evaporation. Ag/AgCl is a second type electrode in which the metal is in contact wit its low soluble salt and the anion of that salt.

How do you clean Ag AgCl reference electrode?

How to clean the GSR Fingerelectrodes (Ag-AgCl)

1. scoop as much of the gel away from the electrode and housing, using a dry cotton swab or two.
2. use a fresh cotton swab dipped in alcohol for cleaning the electrode face and housing.