Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: aristooo on December 18, 2015, 04:56:38 AM
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i was wondering ... what is the mathematical function for a titration curve of a base being neutralized by an acid ( both being strong bases/acids).
for example this curve :
https://www.google.gr/search?q=titration+of+hcl+naoh&espv=2&biw=1920&bih=979&tbm=isch&imgil=6K00BiWpzoo2iM%253A%253BGsmE3OcIRMA83M%253Bhttp%25253A%25252F%25252Fadsorption.org%25252Fawm%25252Futils%25252FCO2.htm&source=iu&pf=m&fir=6K00BiWpzoo2iM%253A%252CGsmE3OcIRMA83M%252C_&usg=__fXOyhXBxENpePkwyr-5tUNoEUmM%3D&ved=0ahUKEwiZ2prYkeXJAhXK1ywKHZ_LB68QyjcIOQ&ei=gNdzVpmaB8qvswGfl5_4Cg#imgrc=Nj_EeHphKcag4M%3A&usg=__fXOyhXBxENpePkwyr-5tUNoEUmM%3D
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Read this discussion
https://www.physicsforums.com/threads/can-titration-curves-be-modeled-with-a-sigmoid-function.157801/
and
http://www.chembuddy.com/?left=pH-calculation&right=titration-curves-calculation
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Like AWK: posted, the curve shape is called a sigmoidal curve. Or s-shaped if you must be non-Greek.:). You can determine the most inflection points algebraically,if you want to know titration endpoints. You can model the fiction with a polynomial fit, especially if there's more than one endpoint.
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In general: there is no reasonably simple function that you can use.
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Read this discussion
https://www.physicsforums.com/threads/can-titration-curves-be-modeled-with-a-sigmoid-function.157801/
and
http://www.chembuddy.com/?left=pH-calculation&right=titration-curves-calculation
thank you. that was really helpful. i asked this because i was trying to figure out why the ph drops significantly around ph=7 and i thought it might be due to the fact that ph is an exponential climax. meaning that if the (H30+) concentration for example is being reduced by 1000 times the ph increases a lot less.