Ask A Scientist Chemistry Archive

name         Jennifer R.
status       educator
age          20s

Question -   I was wondering the range of intensity regarding 
acids. Aomeone said that stomach acid (gastric acid) is the strongest 
acid. This I completely disagree with and was hoping you could clear up 
some general questions about the order in acid strengths ex. 1-sulfuric 
acid 2-battery acid-stomach acid. Thank you for your time and help.
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Hi - I have found that battery acid has a pH of 0.8 (Navel and Ravidi, 
Chemistry, 2nd ed. 1994). Battery acid is 30% sulfuric acid solution with 
a density of 1.28 g/mL. Sulfuric acid is a strong acid and so even though 
it has two protons its pH is reasonably well approximated by pH = -log 
[H2SO4] if it is concentrated - so a 0.71 M solution of H2SO4 would have a 
pH of about 0.15 (see General Chemistry by Hill and Petrucci, 3rd ed., 
2002). Stomach acid ("gastric juice") pH ranges between 1.0 and 3.0 with 
the average being about 1.8; sodas 2.0-4.0; lemon juice 2.2-2.4; vinegar 
2.4-3.4; wine 2.8-3.8; typical drinking water 6.5-8.0.

Battery acid is a stronger acid than stomach acid.

Best, prof. topper
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