Sulfurous acid

<h2 id="history-and-production">History and production</h2>
<p>Sulfurous acid is commonly known not to exist in its free state, and owing to this, it is stated in textbooks that it cannot be isolated in the water-free form.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> However, the molecule has been detected in the gas phase in 1988 by the dissociative ionization of <a href="/facts/Diethyl_sulfite/f28TcvAM">diethyl sulfite</a>.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> The conjugate bases of this elusive acid are, however, common anions, <a href="/facts/Bisulfite/4ojEuJ8N">bisulfite</a> (or hydrogen sulfite) and <a href="/facts/Sulfite/xdppUlKA">sulfite</a>. Sulfurous acid is an intermediate species in the formation of <a href="/facts/Acid_rain/f769GyNz">acid rain</a> from sulfur dioxide.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a>
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<h2 id="uses">Uses</h2>
<p>Aqueous solutions of sulfur dioxide, which sometimes are referred to as sulfurous acid, are used as <a href="/facts/Reducing_agent/CtfSGVXC">reducing agents</a> and as disinfectants, as are solutions of <a href="/facts/Bisulfite/4ojEuJ8N">bisulfite</a> and <a href="/facts/Sulfite/xdppUlKA">sulfite</a> salts. They are <a href="/facts/Oxidisation/Pyd5RVcj">oxidised</a> to <a href="/facts/Sulfuric_acid/Wom6fymJ">sulfuric acid</a> or <a href="/facts/Sulfate/yuWVxsUf">sulfate</a> by accepting another <a href="/facts/Oxygen/acyn6o8r">oxygen</a> atom.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a>
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<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Bisulfite/4ojEuJ8N">Bisulfite</a></li>
<li><a href="/facts/Carbonic_acid/fjjVAhwt">Carbonic acid</a></li>
<li><a href="/facts/Pulp_(paper)/wIlq5nWm">Pulp (paper)</a></li>
<li><a href="/facts/Sulfite_process/edJVxor2">Sulfite paper pulp process</a></li>
<li><a href="/facts/Sulfite/xdppUlKA">Sulfite</a></li>
<li><a href="/facts/Sulfuric_acid/Wom6fymJ">Sulfuric acid</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Jolly, William L. (1991). Modern Inorganic Chemistry (2nd ed.). New York: McGraw-Hill. ISBN 0-07-032768-8. <a href="0-07-032768-8" target="_blank">0-07-032768-8</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Catherine E. Housecroft; Alan G. Sharpe (2008). "Chapter 16: The group 16 elements". Inorganic Chemistry, 3rd Edition. Pearson. p. 520. ISBN 978-0-13-175553-6. <a href="978-0-13-175553-6" target="_blank">978-0-13-175553-6</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Greenwood, Norman  N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 719. ISBN 978-0-08-037941-8. <a href="978-0-08-037941-8" target="_blank">978-0-08-037941-8</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>D. Sülzle; M. Verhoeven; J. K. Terlouw; H. Schwarz (1988). "Generation and Characterization of Sulfurous Acid (H2SO3) and of Its Radical Cation as Stable Species in the Gas Phase". Angew. Chem. Int. Ed. Engl. 27 (11): 1533–4. doi:10.1002/anie.198815331. <a href="/wiki/Angew._Chem._Int._Ed._Engl." target="_blank">/wiki/Angew._Chem._Int._Ed._Engl.</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>McQuarrie; Rock (1987). General Chemistry (2nd ed.). New York: W.H. Freeman and Company. p. 243. ISBN 0-7167-1806-5. <a href="0-7167-1806-5" target="_blank">0-7167-1806-5</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>L. Kolditz, Anorganische Chemie, VEB Deutscher Verlag der Wissenschaften, Berlin 1983, S. 476. <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
</ol>

Sulfurous acid open-in-new

Sulfurous acid