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Equivalent concentrationFrom Wikipedia, the free encyclopedia

(Redirected fromNormality (chemistry))

Inchemistry,the equivalent concentrationor normalityof a solution is defined as themolar concentration

divided by an equivalence factor :

Normality

Contents

[hide]

1 Units

2 Usage

3 Examples

4 Criticism

5 References

Units[edit]

The unit symbol "N" is used to denote "Eq/L" (Equivalent per liter) which is normality. Although losing

favor, medical reporting of serum concentrations in "mEq/L" (=0.001 N) still occurs.

Usage[edit]

There are three common areas where normality is used as a measure of reactive species in solution:

In acid-base chemistry, normality is used to express the concentration of protons (H+) or hydroxide

ions (OH

) in a solution. Here, is anintegervalue. Each solute can produce one or more

equivalents of reactive species when dissolved.

Inredoxreactions, the equivalence factor describes the number ofelectronsthat an oxidizing or

reducing agent can accept or donate. Here, can have a fractional (non-integer) value.

Inprecipitationreactions, the equivalence factor measures the number of ions which will precipitate in

a given reaction. Here, is an integer value.

Normal concentration of an ionic solution is intrinsically connected to theconductivity (electrolytic)through

the equivalent conductivity.

Examples[edit]

http://en.wikipedia.org/w/index.php?title=Normality_(chemistry)&redirect=nohttp://en.wikipedia.org/w/index.php?title=Normality_(chemistry)&redirect=nohttp://en.wikipedia.org/w/index.php?title=Normality_(chemistry)&redirect=nohttp://en.wikipedia.org/wiki/Chemistryhttp://en.wikipedia.org/wiki/Chemistryhttp://en.wikipedia.org/wiki/Chemistryhttp://en.wikipedia.org/wiki/Molar_concentrationhttp://en.wikipedia.org/wiki/Molar_concentrationhttp://en.wikipedia.org/wiki/Molar_concentrationhttp://en.wikipedia.org/wiki/Normality_(chemistry)http://en.wikipedia.org/wiki/Normality_(chemistry)http://en.wikipedia.org/wiki/Normality_(chemistry)http://en.wikipedia.org/wiki/Normality_(chemistry)#Unitshttp://en.wikipedia.org/wiki/Normality_(chemistry)#Unitshttp://en.wikipedia.org/wiki/Normality_(chemistry)#Usagehttp://en.wikipedia.org/wiki/Normality_(chemistry)#Usagehttp://en.wikipedia.org/wiki/Normality_(chemistry)#Exampleshttp://en.wikipedia.org/wiki/Normality_(chemistry)#Exampleshttp://en.wikipedia.org/wiki/Normality_(chemistry)#Criticismhttp://en.wikipedia.org/wiki/Normality_(chemistry)#Criticismhttp://en.wikipedia.org/wiki/Normality_(chemistry)#Referenceshttp://en.wikipedia.org/wiki/Normality_(chemistry)#Referenceshttp://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=1http://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=1http://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=1http://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=2http://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=2http://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=2http://en.wikipedia.org/wiki/Integerhttp://en.wikipedia.org/wiki/Integerhttp://en.wikipedia.org/wiki/Integerhttp://en.wikipedia.org/wiki/Redoxhttp://en.wikipedia.org/wiki/Redoxhttp://en.wikipedia.org/wiki/Redoxhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Precipitation_(chemistry)http://en.wikipedia.org/wiki/Precipitation_(chemistry)http://en.wikipedia.org/wiki/Precipitation_(chemistry)http://en.wikipedia.org/wiki/Conductivity_(electrolytic)http://en.wikipedia.org/wiki/Conductivity_(electrolytic)http://en.wikipedia.org/wiki/Conductivity_(electrolytic)http://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=3http://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=3http://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=3http://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=3http://en.wikipedia.org/wiki/Conductivity_(electrolytic)http://en.wikipedia.org/wiki/Precipitation_(chemistry)http://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Redoxhttp://en.wikipedia.org/wiki/Integerhttp://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=2http://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=1http://en.wikipedia.org/wiki/Normality_(chemistry)#Referenceshttp://en.wikipedia.org/wiki/Normality_(chemistry)#Criticismhttp://en.wikipedia.org/wiki/Normality_(chemistry)#Exampleshttp://en.wikipedia.org/wiki/Normality_(chemistry)#Usagehttp://en.wikipedia.org/wiki/Normality_(chemistry)#Unitshttp://en.wikipedia.org/wiki/Normality_(chemistry)http://en.wikipedia.org/wiki/Molar_concentrationhttp://en.wikipedia.org/wiki/Chemistryhttp://en.wikipedia.org/w/index.php?title=Normality_(chemistry)&redirect=no

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Normality can be used for acid-base titrations. For example,sulfuric acid(H2SO4) is adiprotic acid.Since

only 0.5 mol of H2SO4are needed to neutralize 1 mol of OH-, the equivalence factor is:

(H2SO4) = 0.5

If the concentration of a sulfuric acid solution is c(H2SO4) = 1 mol/L, then its normality is 2 N. It canalso be called a "2 normal" solution.

Similarly, for a solution with c(H3PO4) = 1 mol/L, the normality is 3 N becausephosphoric

acidcontains 3 acidic H atoms.

Criticism[edit]

Normality is an ambiguous measure of theconcentrationof a solution. It needs a definition of the

equivalence factor, which depends on the definition ofequivalents.The same solution can

possess differentnormalities for differentreactions. The definition of the equivalence factor varies

depending on the type of chemical reaction that is discussed: It may refer to equations, bases, redox

species, precipitating ions, or isotopes. For example, a solution of MgCl2that is 2 N with respect to a

Cl

ion, is only 1 N with respect to an Mg2+

ion. Since may not be

unequivocal,IUPACandNISTdiscourage the use of normality.[1]

http://en.wikipedia.org/wiki/Sulfuric_acidhttp://en.wikipedia.org/wiki/Sulfuric_acidhttp://en.wikipedia.org/wiki/Sulfuric_acidhttp://en.wikipedia.org/wiki/Diprotic_acidhttp://en.wikipedia.org/wiki/Diprotic_acidhttp://en.wikipedia.org/wiki/Diprotic_acidhttp://en.wikipedia.org/wiki/Phosphoric_acidhttp://en.wikipedia.org/wiki/Phosphoric_acidhttp://en.wikipedia.org/wiki/Phosphoric_acidhttp://en.wikipedia.org/wiki/Phosphoric_acidhttp://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=4http://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=4http://en.wikipedia.org/wiki/Concentrationhttp://en.wikipedia.org/wiki/Concentrationhttp://en.wikipedia.org/wiki/Concentrationhttp://en.wikipedia.org/wiki/Equivalent_(chemistry)http://en.wikipedia.org/wiki/Equivalent_(chemistry)http://en.wikipedia.org/wiki/Equivalent_(chemistry)http://en.wikipedia.org/wiki/IUPAChttp://en.wikipedia.org/wiki/IUPAChttp://en.wikipedia.org/wiki/IUPAChttp://en.wikipedia.org/wiki/NISThttp://en.wikipedia.org/wiki/NISThttp://en.wikipedia.org/wiki/NISThttp://en.wikipedia.org/wiki/Normality_(chemistry)#cite_note-1http://en.wikipedia.org/wiki/Normality_(chemistry)#cite_note-1http://en.wikipedia.org/wiki/Normality_(chemistry)#cite_note-1http://en.wikipedia.org/wiki/Normality_(chemistry)#cite_note-1http://en.wikipedia.org/wiki/NISThttp://en.wikipedia.org/wiki/IUPAChttp://en.wikipedia.org/wiki/Equivalent_(chemistry)http://en.wikipedia.org/wiki/Concentrationhttp://en.wikipedia.org/w/index.php?title=Equivalent_concentration&action=edit&section=4http://en.wikipedia.org/wiki/Phosphoric_acidhttp://en.wikipedia.org/wiki/Phosphoric_acidhttp://en.wikipedia.org/wiki/Diprotic_acidhttp://en.wikipedia.org/wiki/Sulfuric_acid