Electrode Measurements
What is the definition of potentiometry?
measurement of the electrical potential difference between two
electrodes in an
electrochemical cell, when no current is
allowed to flow.
What is the definition of oscillating reactions?
in which chemical concentrations oscillate between high and low values.
What is the definition of junction potential?
When two dissimilar electrolyte solutions are placed in contact, a voltage difference develops at the interface.
What is the difference between direct and relative potentiometric measurements?
Direct
Liquid-liquid junction at 4% among 14 measurements by direct potentiometry
Relative
What is a junction potential?
What are double-junction reference electrodes used for?
typically used for ISE [Ion selective electrode] analysis where the leached electrolyte must not interfere with the ISE being used.
They are also particularly useful for pH analysis of products that must not have KCl or a strong electrolyte contaminating the sample
What is an ISE and what are some advantages?
is an analytical technique used to determine the activity of ions in aqueous solution by measuring the electrical potential.
What is the function of an ISE (Ion-selective electrode)?
selectively binds one ion—no redox chemistry
What is the function of a Metal electrode?
It is a surface on which redox reaction takes place.
How does a glass pH electrode work?
What are different errors of pH measurement?
What is a combination electrode?
incorporating both the glass and reference electrodes in one body
What should be done to pH electrode before use?
They must be calibrated before use. It should be calibrated every 2 h in sustained use. Ideally, calibration standards should bracket the pH of the unknown.
What should you not do to a glass electrode?
Don’t leave it out of water (or in a nonaqueous solvent) longer than necessary.
What are some advantages and disadvantages of ISE (Ion-selective electrode)?
Advantages:
Disadvantages:
What is a solid-state ion-selective electrode?
What is a liquid-based ion-selective electrode?
What is a compound electrode?
a conventional electrode surrounded by a membrane that isolates (or generates) the analyte to which the electrode responds.
What are the different types of membrane electrodes?
There are four main types of ion-selective membrane used in ion-selective electrodes (ISEs): glass, solid state, liquid based, and compound electrode.
What is the quantity, method, and analyte for potentiometry?
What is the quantity, method, and analyte for coulometry?
What is the quantity, method, and analyte for amperometry?
What is the quantity, method, and analyte for voltammetry?