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[[Category:Done 2018-07-20]]  
[[File:bleachs.JPG|160px|thumb|Figure 1. Bleach has a pH of around 12-13.]]
[[File:bleachs.JPG|160px|thumb|Figure 1. Bleach has a pH of around 12-13.]]


<onlyinclude>A '''base''' or '''alkaline''' is defined as any substance with a [[pH]] greater than 7. This means that the [[ion]] concentration of [[hydrogen]] (H<sup>+</sup>) is less than the concentration of hydroxide (OH<sup>-</sup>).</onlyinclude> A higher pH means a higher basicity, and thus a higher concentration of OH<sup>-</sup> ions in the solution. These types of substances exhibit distinct properties: they feel slippery and have a bitter taste when ingested.<ref name=ucd>UC Davis Chem Wiki. (July 8, 2015). ''Acid/Base Basics'' [Online], Available: http://chemwiki.ucdavis.edu/Physical_Chemistry/Acids_and_Bases/Acid#Neutralization</ref>
<onlyinclude>A '''base''' or '''alkaline''' is any substance that will react with water to produce OH<sup>-</sup><ref name=libre>Chemistry LibreTexts. (July 11 2018). ''Overview of Acids and Bases'' [online], Available:https://chem.libretexts.org/Textbook_Maps/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Acids_and_Bases/Acid/Overview_of_Acids_and_Bases </ref> Generally, solutions of bases in water will have a [[pH]] greater than 7.


When mixed with an [[acid]], the pH of the new solution will balance out towards the neutral pH of 7, depending on the strength of the acid and base. This is known as neutralization.<ref name=ucd/>
In water, there is always some H<sup>+</sup> and OH<sup>-</sup> [[ion]]s in solution due to the self-ionization of water. In basic solutions, there will be more OH<sup>-</sup> than H<sup>+</sup>. More concentrated bases will have more OH<sup>-</sup> in solution. Following the pH scale, a more basic solution - one with more OH<sup>-</sup> - will have a <em>higher</em> pH value. </onlyinclude>[[Acid]]s can react with bases in a [[neutralization]] reaction, where the H<sup>+</sup> from the acid reacts with the OH<sup>-</sup> of the base to produce a solution with a lower OH<sup>-</sup> concentration - and a lower pH - than the original base solution.  
 
Most common inorganic bases are hydroxides (containing OH<sup>-</sup> in their composition), such as sodium hydroxide, NaOH, or calcium hydroxide, Ca(OH)<sub>2</sub>. However some [[organic molecule|organic]] bases exist, such as ammonia-based molecules like amines, that do not contain OH<sup>-</sup> directly: any OH<sup>-</sup> in a solution of these molecules is formed from a reaction with water. <ref name=libre3>Chemistry LibreTexts. (July 11, 2018). ''Organic Acids and Organic Bases'' [online], Available: https://chem.libretexts.org/Textbook_Maps/Organic_Chemistry/Map%3A_Organic_Chemistry_(McMurry)/chapter_02%3A_Polar_Covalent_Bonds%3B_Acids_and_Bases/2.10_Organic_Acids_and_Organic_Bases#Ammonia_as_a_weak_base </ref>


===Uses===
===Uses===


Bases have many uses, alongside their neutralizing abilities for acidic substances, such as when [[acid rain]] is neutralized by stones and minerals with a high pH. Some uses include:
The ability of bases to [[neutralization|neutralize]] acids is very useful, as many reactions and industrial processes have acidic waste products. Some examples of using bases to neutralizing unwanted acids:
*[[Acid rain]] can be neutralized by basic minerals, such as limestone. (Limestone is mainly calcium carbonate.<ref name=geo>Geology.com. (July 11, 2018). ''Limestone'' [online], Available: https://geology.com/rocks/limestone.shtml</ref>)
*[[Scrubber]]s used in [[power plant]]s use bases (e.g. calcium hydroxide) in order to reduce the release of [[sulfur oxides]] (a type of acidic [[pollutant]]) produced by the plant.
*Antacids contain bases (most often calcium carbonate) that react with stomach acid in order to treat heartburn and indigestion. <ref name=libre2>Chemistry Libretexts. (July 11, 2018). ''Heartburn'' [online], Available: https://chem.libretexts.org/Textbook_Maps/General_Chemistry/Map%3A_A_Molecular_Approach_(Tro)/16%3A_Acids_and_Bases/16.01%3A_Heartburn</ref>


*[[Scrubber]]s used in [[power plant]]s make use of certain bases like Calcium hydroxide in order to chemically clean the [[sulfur oxides]] (a type of [[pollutant]]) produced by the plant.
Outside of neutralization, bases are also used in chemical reactions:
*Antacids containing magnesium hydroxide are ingested in order to balance out [[acid]]ity in the stomach in order to cure indigestion.
 
*Sodium hydroxide is used to make soaps, while calcium hydroxide is used to make bleaching powder.
*Sodium hydroxide and potassium hydroxide are used to make soaps. <ref name=soap>Ogden Publications Inc. (July 11, 2018). ''Mother Earth Living: Honey and Beeswax Soap Recipe'' [online], Available: https://www.motherearthliving.com/health-and-wellness/beauty-recipes/honey-and-beeswax-soap-recipe-ze0z1506zdeb</ref>
*Sodium hydrogen carbonate (baking soda) has many applications.
*Sodium hypochlorite (NaOCl) is the main ingredient in laundry bleach. <ref name=bleach>Chlorox. (July 11, 2018). ''What is bleach?'' [online], Available: https://www.clorox.com/how-to/laundry-basics/bleach-101/bleach/ </ref>
*Sodium bicarbonate (baking soda) is used to generate gases for leavening bread and baked goods, and in some fire extinguishers. <ref name=fire>Piper Fire Protection Inc. (July 11, 2018). ''Types of Fire Extinguishers and What They Do''. [online]. Available: http://www.piperfire.com/types-of-fire-extinguishers-and-what-they-do/</ref>


[[File:pHacid.png|800px|thumb|center|Figure 2. Various acids and bases on the pH scale.<ref>Adapted from Energy: Its use and the Environment -- R. A. Hinrichs and M. Kleinbach, "Acid Rain," in ''Energy: Its Use and the Environment'', 5th ed. Toronto, Ont. Canada: Brooks/Cole, 2006, ch.8, sec.C, pp.252-256</ref>]]
[[File:pHacid.png|800px|thumb|center|Figure 2. Various acids and bases on the pH scale.<ref>Adapted from Energy: Its use and the Environment -- R. A. Hinrichs and M. Kleinbach, "Acid Rain," in ''Energy: Its Use and the Environment'', 5th ed. Toronto, Ont. Canada: Brooks/Cole, 2006, ch.8, sec.C, pp.252-256</ref>]]


To learn more about acids and bases please see [http://chemwiki.ucdavis.edu/Physical_Chemistry/Acids_and_Bases UC Davis's chem wiki].
To learn more about acids and bases please see [https://chem.libretexts.org/Textbook_Maps/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Acids_and_Bases/Acid/Overview_of_Acids_and_Bases the Chemistry LibreText].
 
==Phet Simulation==
The [http://phet.colorado.edu/ University of Colorado] has graciously allowed us to use the following Phet simulation. Explore this simulation to see how the pH of acids and bases work.
 
<html>
<iframe src="https://phet.colorado.edu/sims/html/acid-base-solutions/latest/acid-base-solutions_en.html" width="800" height="600"></iframe>
</html>
 
==For Further Reading==
*[[Acid]]
*[[The pH scale]]
*[[Chemical]]
*[[Water]]
*[[Acid rain]]
*[[Water cycle]]
*Or explore a [[Special:Random|random page]]


To learn more about acids and bases please see [https://chem.libretexts.org/Textbook_Maps/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Acids_and_Bases/Acid/Overview_of_Acids_and_Bases the Chemistry LibreText].
==References==
==References==
{{Reflist}}
{{reflist}}
[[Category:Uploaded]]

Revision as of 02:04, 13 July 2018

Figure 1. Bleach has a pH of around 12-13.

A base or alkaline is any substance that will react with water to produce OH-[1] Generally, solutions of bases in water will have a pH greater than 7.

In water, there is always some H+ and OH- ions in solution due to the self-ionization of water. In basic solutions, there will be more OH- than H+. More concentrated bases will have more OH- in solution. Following the pH scale, a more basic solution - one with more OH- - will have a higher pH value. Acids can react with bases in a neutralization reaction, where the H+ from the acid reacts with the OH- of the base to produce a solution with a lower OH- concentration - and a lower pH - than the original base solution.

Most common inorganic bases are hydroxides (containing OH- in their composition), such as sodium hydroxide, NaOH, or calcium hydroxide, Ca(OH)2. However some organic bases exist, such as ammonia-based molecules like amines, that do not contain OH- directly: any OH- in a solution of these molecules is formed from a reaction with water. [2]

Uses

The ability of bases to neutralize acids is very useful, as many reactions and industrial processes have acidic waste products. Some examples of using bases to neutralizing unwanted acids:

  • Acid rain can be neutralized by basic minerals, such as limestone. (Limestone is mainly calcium carbonate.[3])
  • Scrubbers used in power plants use bases (e.g. calcium hydroxide) in order to reduce the release of sulfur oxides (a type of acidic pollutant) produced by the plant.
  • Antacids contain bases (most often calcium carbonate) that react with stomach acid in order to treat heartburn and indigestion. [4]

Outside of neutralization, bases are also used in chemical reactions:

  • Sodium hydroxide and potassium hydroxide are used to make soaps. [5]
  • Sodium hypochlorite (NaOCl) is the main ingredient in laundry bleach. [6]
  • Sodium bicarbonate (baking soda) is used to generate gases for leavening bread and baked goods, and in some fire extinguishers. [7]
Figure 2. Various acids and bases on the pH scale.[8]

To learn more about acids and bases please see the Chemistry LibreText.

Phet Simulation

The University of Colorado has graciously allowed us to use the following Phet simulation. Explore this simulation to see how the pH of acids and bases work.

For Further Reading

To learn more about acids and bases please see the Chemistry LibreText.

References

  1. ↑ Chemistry LibreTexts. (July 11 2018). Overview of Acids and Bases [online], Available:https://chem.libretexts.org/Textbook_Maps/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Acids_and_Bases/Acid/Overview_of_Acids_and_Bases
  2. ↑ Chemistry LibreTexts. (July 11, 2018). Organic Acids and Organic Bases [online], Available: https://chem.libretexts.org/Textbook_Maps/Organic_Chemistry/Map%3A_Organic_Chemistry_(McMurry)/chapter_02%3A_Polar_Covalent_Bonds%3B_Acids_and_Bases/2.10_Organic_Acids_and_Organic_Bases#Ammonia_as_a_weak_base
  3. ↑ Geology.com. (July 11, 2018). Limestone [online], Available: https://geology.com/rocks/limestone.shtml
  4. ↑ Chemistry Libretexts. (July 11, 2018). Heartburn [online], Available: https://chem.libretexts.org/Textbook_Maps/General_Chemistry/Map%3A_A_Molecular_Approach_(Tro)/16%3A_Acids_and_Bases/16.01%3A_Heartburn
  5. ↑ Ogden Publications Inc. (July 11, 2018). Mother Earth Living: Honey and Beeswax Soap Recipe [online], Available: https://www.motherearthliving.com/health-and-wellness/beauty-recipes/honey-and-beeswax-soap-recipe-ze0z1506zdeb
  6. ↑ Chlorox. (July 11, 2018). What is bleach? [online], Available: https://www.clorox.com/how-to/laundry-basics/bleach-101/bleach/
  7. ↑ Piper Fire Protection Inc. (July 11, 2018). Types of Fire Extinguishers and What They Do. [online]. Available: http://www.piperfire.com/types-of-fire-extinguishers-and-what-they-do/
  8. ↑ Adapted from Energy: Its use and the Environment -- R. A. Hinrichs and M. Kleinbach, "Acid Rain," in Energy: Its Use and the Environment, 5th ed. Toronto, Ont. Canada: Brooks/Cole, 2006, ch.8, sec.C, pp.252-256
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