Lecture 11

Question 1

A glass electrode, pH electrode, is coated inside and out with a layer of hydrated gel.

Ion exchange takes place on the surface.
What properties allows for measurement of pH?

Answer 1

protons in the water exchange for sodium ions in the glass

Question 2

The best possible accuracy which can be obtained in the measurement of pH is:

Answer 2

± 0.02 pH units

Question 3

True or false
An Ion Selective Electrode (ISE) is a sensor that converts the activity of a specific ion in a solution into an electrical potential, which can then be measured by a voltmeter or pH meter.

Answer 3

True

Question 4

What type of electrode is used to determine ion concentrations

Answer 4

ion selective electrode,

Question 5

What type of electrode has a stable and well-known electrode potential

Answer 5

reference electrode,

Question 6

What type of electrode is sensitive to the ion to be determined

Answer 6

indicator electrode

Question 7

The voltage measured using an ISE is theoretically dependent on what?

Answer 7

log of the ionic activity

Question 8

True or false
Ion Selective Electrodes can be used across the full pH range, from 0-14

Answer 8

False

Question 9

True or false

A glass electrode is used to measure pH (i.e. [H+])

It is not subject to interference and can be used from pH = 0 to pH = 14 without issue.

Answer 9

False