Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Edher on March 09, 2005, 05:36:15 PM
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Saludos,
What volume of 0.146 M KOH is needed for the complete neutralization of 20.00 mL of 0.0942 M H2SO4?
This is how I solved it,
20 mL x 0.0942 M H2SO4 = 1.884 mmol H2SO4
XmL x 0.146 mmol = 1.884 mmol KOH
1 mL
I got X = 12.9 mL. However, the book says it should be double that 25.8 mL. Why is that?
Thank You,
Edher
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You are forgetting that H2SO4 is a diprotic acid (ie gives up 2 moles of H+ for every mole of H2SO4)!!
Your calculations took into account only half of the protons given up by H2SO4, therefore the answer was double what you calculated. :)
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Froggirl,
I had a feeling that it had something to do with diprotic acids but since I missed that lecture I wasn't quite certain on how to apply its properties. Thank you.
Edher
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a monoprotic acid gives out 1 proton per molecule
a diprotic acid gives 2 protons per molecule
hence, the same concentration if a strong diprotic acid gives u twice as much H+ of a strong monoprotic acid.