1 normal acid or base (1N)

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(molarity)
Current revision (17:05, 27 February 2012) (view source)
(1N, 2N HCl)
 
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Biologists are sometimes confused by the non-standard[http://physics.nist.gov/cuu/Units/checklist.html] chemical unit of '''normality N'''. N refers in general to salts while it's most commonly used in the context of acid and bases.
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Biologists are sometimes confused by the non-standard[http://physics.nist.gov/cuu/Units/checklist.html] chemical unit of '''normality N'''. N refers in general to salts while it's most commonly used in the context of acid and bases. N can refere to either the cation or the anion in a hydrolysis. In the context of acid and bases it is generally assumed that N refers to the proton or the hydroxide ion.
* 1 M (mol/l) = 1 N for an acid that releases 1 proton* when dissolved in water, e.g. HCL (*monoprotic)
* 1 M (mol/l) = 1 N for an acid that releases 1 proton* when dissolved in water, e.g. HCL (*monoprotic)
* 1 M (mol/l) = ''2'' N for an acid that releases 2 protons*, e.g. H<sub>2</sub>SO<sub>4</sub> (*diprotic)
* 1 M (mol/l) = ''2'' N for an acid that releases 2 protons*, e.g. H<sub>2</sub>SO<sub>4</sub> (*diprotic)
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By the way, ''molarity M'' is also a non-standard unit[http://physics.nist.gov/cuu/Units/checklist.html]. Expressing this explicitly as mol/L or mol/m<sup>3</sup> is clearer to reader less used to biological customs.
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For example, some antigen retrieval methods use 2N hydrochloric acid to open up the tissue to allow antibody binding. This could be a nucleotide analogue, as BrdU or dUTP-TMR in cell proliferation of apoptosis assays.
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{| {{table}} OR border=1 cellpadding=5 cellspacing=0 OR {{sorttable}}
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! style="background:lightgrey"|acid/case
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! style="background:lightgrey"|molecular weight
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! style="background:lightgrey"|N vs M
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|-
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| HCl -> <font color=blue>1·H<sup>+</sup></font> + Cl<sup>-</sup>
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| 36.5 g/mol
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| 1N = 1M = 36.5g/L
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|-
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| H<sub>2</sub>SO<sub>4</sub> -> <font color=blue>2·H<sup>+</sup></font> + SO<sub>4</sub><sup>2-</sup>
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| 98 g/mol
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| 2N = 1M = 98g/L
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|-
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| NaOH -> Na<sup>+</sup> + <font color=blue>1·OH<sup>-</sup></font>
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| 40 g/mol
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| 1N = 1M = 40g/L
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|}
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== 1N, 2N HCl ==
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1N HCl
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* 8.3 ml fuming HCl (37% v/v = ~12N = ~12M)
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* 91.7 ml H<sub>2</sub>O
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2N HCl, see also [http://www.ihcworld.com/_protocols/epitope_retrieval/hcl.htm]
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* 16.5 ml fuming HCl (37% v/v = ~12N = ~12M)
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* 83.5 ml H<sub>2</sub>O
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== Molarity (M) also a non-standard unit ==
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For the nitpickers, ''molarity M'' is also a non-standard unit[http://physics.nist.gov/cuu/Units/checklist.html]. Expressing this explicitly as mol/L or mol/m<sup>3</sup> is clearer to readers less versed in current biological customs.
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==See also==
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* [http://en.wikipedia.org/wiki/Concentration#Normality Normality section of Concentration page at the Wikipedia]
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* [http://physics.nist.gov/cuu/Units/units.html International standard units, SI units]
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* [http://www.histosearch.com/histonet/Dec03A/RE.HistonetnormalsolutionA.html Example student question & answer]
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[[Category:Chemical]]
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[[Category:Material]]
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[[Category:Acid]]

Current revision

Biologists are sometimes confused by the non-standard[1] chemical unit of normality N. N refers in general to salts while it's most commonly used in the context of acid and bases. N can refere to either the cation or the anion in a hydrolysis. In the context of acid and bases it is generally assumed that N refers to the proton or the hydroxide ion.

  • 1 M (mol/l) = 1 N for an acid that releases 1 proton* when dissolved in water, e.g. HCL (*monoprotic)
  • 1 M (mol/l) = 2 N for an acid that releases 2 protons*, e.g. H2SO4 (*diprotic)

For example, some antigen retrieval methods use 2N hydrochloric acid to open up the tissue to allow antibody binding. This could be a nucleotide analogue, as BrdU or dUTP-TMR in cell proliferation of apoptosis assays.

acid/case molecular weight N vs M
HCl -> 1·H+ + Cl- 36.5 g/mol 1N = 1M = 36.5g/L
H2SO4 -> 2·H+ + SO42- 98 g/mol 2N = 1M = 98g/L
NaOH -> Na+ + 1·OH- 40 g/mol 1N = 1M = 40g/L

1N, 2N HCl

1N HCl

  • 8.3 ml fuming HCl (37% v/v = ~12N = ~12M)
  • 91.7 ml H2O

2N HCl, see also [2]

  • 16.5 ml fuming HCl (37% v/v = ~12N = ~12M)
  • 83.5 ml H2O

Molarity (M) also a non-standard unit

For the nitpickers, molarity M is also a non-standard unit[3]. Expressing this explicitly as mol/L or mol/m3 is clearer to readers less versed in current biological customs.

See also

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