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IS 1885-73-2 (1993): Electrotechnical Vocabulary, Part 73:Physics and chemistry, Section 02: Electrotechnicalconcepts [ETD 1: Basic Electrotechnical Standards]

IS 1885 ( Part 73/Set 2 ) : 1993 IEC Pub 50 (III-02 ) ( 1984 )

wmfs w-s

Indian Standard

ELECTROTECHNTCALVOCABULARY PART 73 PHYSICS AND CHEMISTRY

Section 2 Electrochemical Concepts

UDC 54.13 : 621.35 : 001.4

BURE MANAK

May 1993

CQ BIS 1993

AU OF INDIAN STANDARDS BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

Price Group 2

Basic Electrotechnical Standards Sectional Committee, ET 01

NATIONAL FOREWORD

This Indian Standard ( Part 73/Set 2 ) which is identical with IEC Pub 50 ( 11 l-01 ) ( 1984 ) Inter- national electrotechnical vocabulary - Chapter 111 : Physics and chemistry, Se&ion 02 : Electro- chemical concepts, issued by the International Electrotechnical Commission ( IEC ), was adopted by the Bureau of Indian Standards on the recommendation of the Basic Electrotechnical Standards Sectional Committee and approval of the Electrotechnical Division Council.

Only the English text given in the IEC publication has been retained while adopting as Indian Standard, and as such the page numbers given here are not same as in IEC publication.

IS 1885 (Part 73/Set 2) : 1993 IEC Pub 50 (W-02) : 1984

Indian Standard

ELECTROTECHNICALVOCABULARY PART 73 PHYSICS AND CHEMISTRY

Section 2 Electrochemical Concepts

EXPLANATORY NOTE

The purpose of IEV advance editions is to permit the issue without loss of time of terminology work whose publication would otherwise be delayed and, in particular, work which does not exactly correspond to the general plan of the IEV; for example, incomplete chapters, vocabularies extending beyond the framework of a normal chapter or work relating to rapidly evolving fields. Advance editions may, in certain cases, be incomplete, particularly as regards the Russian text and the terms in the additional languages, when the appropriate information is not available at the time of printing.

111-02-01

electrochemistry

That branch of science and technology which deals with reciprocal transformation of chemical and electric energy.

111~02-02

electrolyte

A liquid or solid phase containing mobile ions which rende,r the phase ionically conductive.

111-02-03

electrode

Aconducting part forming an interface with a medium of different conductivity.

ill-02-04[05] oxidation [reduction]

A reaction removing [adding] electrons from [to] atoms, molecules or ions.

111-02-06

electrode reaction

A reaction involving the transfer of charge between electrolyte and electrode.

111-02-07 active surface of an electrode

The interface between the electrolyte and the electrode where the electrode reaction takes place.

111-02-08

side reaction

PUI electrode reaction which occurs in addition to the main process.

111-02-09

anodic reaction (elctrochemical) oxidation

An electrode reaction at the interface of which electrons are supplied to it by the elctrolyte and flow into the external circuit.

lli-02-10 cathodic reaction (elctrochemical) reduction

An electrode reaction at the interface of which electrons from the external circuit are supplied to the electrolyte.

111-02-11

ion

Any atom or bonded group of atoms that has a net electric charge.

111-02-12 [13] anion [cation]

A negatively [positively] charged ion.

111-02-14

(electrochemical) cell

A heterogeneous system in which electric energy produces chemical reaction or, conversely, in which chemical reactions produce electric energy.

111-02-15

galvanic cell

voltaic cell (deprecated)

An elctrochemical cell capable of converting chemical energy into electric energy.

111-02-16

electrolysis cell

An electrochelnical cell capable of producing a chemi- cal reaction when electric energy is supplied.

111-02-17 cell voltage

The voltage measured at the terminals of a cell.

111-02-18

(cell) source voltage

cell e.m.f.

The cell voltage measured at zero current.

111-02-19

electrode potential

The difference between the internal electric potentials of the electrode and of the electrolyte. Note. -This voltage cannot be measured directly.

1

IS 1885 (Part 73/Set 2) : 1993

IEC I'llll 50 (ill-02) (1984)

111-02-20

equilibrium (electrode) potential

The electrode potential when the electrode reaction is at equilibrium.

111-02-21 standard (electrode) potential

An equilibrium electrode potential under standardized chemical and physical conditions.

111-02-22 (electrode) polarization

The difference between the potential of an electrode and its equilibrium potential.

111-02-23 [24]

anodic [cathodic] polarization

An electrode polarization associated with an anodic [a cathodic] reaction.

111-02-25

cell polarization

The sum of the absolute values of anodic and cathodic polarization.

M-02-26

active material

Any material which undergoes electrode reaction in a cell and enables chemical energy to be converted into electric energy when the cell discharges. Note. - In a secondary cell the active materials are restored to their original composition on recharge.

111-02-27

(apparent) internal resistance (of a cell)

For a cell, the quotient of the change of voltage to the corresponding change of current, under specified con- ditions.

111-02-28 end (point) voltage

cut-off voltage (USA)

The conventional voltage, mckured at the terminals of a cell, at which the discharge of the cell on a specified load is considered finished.

111-02-29

capacity (of a galvanic cell)

The quantity of electricity which can be delivered by an electrochemical cell under specified conditions. Note. - The capacity is often expressed in ampere hours (Ah).

111-02-30 ion concentration

The amount of ionic substance of a specific type per unit volume of a solution.

111-02-31 ion activity

The ion concentration corrected for the deviation be- tween the actual and the ideal solution.

111-02-32

activity factor

activity coefficient (deprecated)

The ratio of tde ion activity to the ion concentration.

111-02-33

molality (of solute ;) (bi)

The amount of solute substance i per unit mass of the solvent.

111-02-34 ionic strength (of a solution) (I)

The half-sum of the products of the molalities bi of all ions by the squares of the numbers of their respective elementary charges Zi :

I=;Xbizi 2

111-02-35

reference electrode

Electrode with a well-defined and constant equilibrium potential against which it is possible to measure or calculate other electrode potentials by including them in an appropriate cell.

111-02-36

hydrogen electrode

Platinized platinum electrode saturated by a stream of pure gaseous hydrogen.

111-02-37

standard hydrogen electrode

A hydrogen electrode in contact with an electrolyte of hydrogen ion activity equal to one and with the hydrogen gas at a pressure of 101325 kPa (1 atm). Note. -By convention the potential of this electrode is zero at any temperature.

111-02-38

double-layer

The model representing the structure of an electrolyte at the electrode interface comprising a rigid layer, called Helmholtz layer, and a diffuse layer, called Gouy layer.

111-02-39

diffuse layer potential ; zeta potential

The potential difference across the face between the rigid layer and the diffuse layer of the electrolyte.

111-02-40 Gibbs free energy ; Gibbs function (G)

The function of state equal to the difference between the enthalpy, of a body and the product of its entropy by the temperature.

G=H-TS

2

111-02-41 electro-osmosis

The movement of a fluid through a diaphragm produced by application of an electric field.

111-02-42 electrocapillarity

The change of the mechanical stress at the surface between two bodies due to the presence of charges at the interface.

111-02-43

PH Anumber quantifying the acid or the alkaline character of a solution, conventionally expressed by the decimal logarithm of the ratio of the ign activity of a hydrogen cation under standardized conditions to the actual ion activity of the same cation. Note. - Aqueous solutions with a pH :

- less than 7 are acid, - equal to 7 are neutral, - greater than 7 are alkaline.

111-02-44 immunity

A thermodynamic state by which electrochemical cor- rosion is made impossible.

U-02-45

passivity

The state of a surface of a metal by which its electrochemical corrosion becomes negligible.

U-02-46

cathodic protection

An immunity produced by an appropriate cathodic polarization.

IS 1885 (Part 73/Set 2) : 1993

IEC Pub 50 (U-02) (1984)

111-02-47

(electrochemical) migration

The transport of charged particles due to the effect of an electric field.

111-02-48 (chemical or electrochemical) diffusion

The transport of particles due to the effect of a con- centration gradient.

111-02-49 adsorption

An increased concentration of any component at the surface of a liquid or solid.

111-02-50

dendrite t

A needle or branching, tree-like formation of crys- talline growth formed during electrochemical deposifion.

111-02-51

separator

In an electrochemical cell, a device made of an insulat- ing material permeable to the ions of the electrolyte and prohibiting totally or partially the mixing of the materials. Note. - Membranes and diaphragms are special forms of separators.

111-02-52 spacer; separation

A device made of insulating material used to main- tain the spacing between electrodes of opposite polarity.

IS 1885 (Part 73/&c 2) : 1993

IEC Pub 50 (111-02) (1984)

INDEX

A

active material active surface of an electrode

*a&&y coefficient (deprecated) activity factor adsorption anion anodic polarization anodic reaction (apparent) internal resistance (of a cell)

C

electro-osmosis

111-02-26 end (point) voltage

11 l-02-87 equilibrium (electrode) potential

111-02-32 G

111-02-32 galvanic cell 111-02-49 111-02-12

Gibbs free energy

111-02-u Gibbs function (G)

111-02-09 H

11 l-02-27 hydrogen electrode

I

capacity (of a galvanic cell) 111-02-29 cathodic polarization 11 l-02-24 cathodic protection 111-02-46 cathodic reaction 111-02-10 cation 111-02-13 cell e.m.f. (deprecated) 111-02-18 cell polarization 111-02-2s (cell) source voltage 111-02-18 cell voltage 111-02-17 (chemical or electrochemical) diffusion 111-02-48 cut-off voltage (USA) 111-0228

D

dendrite diaphragm (see separator) diffuse layer potential double-layer

E

111-02-50 111-02-51

111-02-39 111-02-38

electrocapillarity 11 l-02-42

(electrochemical) cell 111-02-14

(electrochemical) migration 11 l-02-47 (electrochemical) oxidation 11 L-02-09

(electrochemical) reduction 111-02-10

electrochemistry 111-02-01

electrode 11 l-02-03 (electrode) polarization 11 l-02-22

electrode potential 111-02-19

electrode reaction 11 l-02-06 electrolysis cell 111-02-16 electrolyte 11 l-02-02

immunity ion ion activity ion concentration ionic strength (of a solution) (I)

M

membrane (see separator) molality (of solute I)

0

oxidation

P

PH passivity

R

reduction reference electrode

s

separation

separator side reaction spacer standard (electrode) potential standard hydrogen electrode

Y

voltaic cell (deprecated)

Z

zeta potential

111-02-41 111-02-28 11 l-02-20

111-02-15 11 l-02-40 111-02-4.0

111-02-36

111-02-44 111-02-11 111-02-31 111-02-U) 111-02-34

ill-02-51 111-02-33

111-02-04

11 l-02-43 111-02-45

111-02-05 111-02-35

111-02-52

111-02-51 111-02-08 111-02-52 11 l-02-21 11 l-02-37

111-02-15

11 l-02-39

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