Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Zonico on January 19, 2020, 03:22:18 PM
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Hello guys,
I'm doing a presentation in school about pH and acids and bases. Right now, I have a question about the ion product of water and I hope some of you can help me out with that.
So, it's clear that the ion product in a neutral solution is 10^14. But for the equations about the potency of acids and bases, the ion product has to be the same as well because pKs + pKb = 14. But I don't understand why that's the case from a reaction's standpoint.
In school, we learnt that you can move the reaction balance point by increasing/decreasing the concentration of one of the educts/products.
But that's exactly what changing the pH/making a solution acidic/basic is, so shouldn't that change the balance point of the reaction from water to oxoniumions and hydroxidions.
Because that would then result in a change of the ion product.
Can someone make out where I'm wrong here? Thank you all very much, I greatly appreciate any *delete me*
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Water autodissociation is an equilibrium process and water ions product is just an equilibrium constant.
And its value is 10-14.
But that's exactly what changing the pH/making a solution acidic/basic is, so shouldn't that change the balance point of the reaction from water to oxoniumions and hydroxidions.
Because that would then result in a change of the ion product.
Quite the opposite, if one grows, the other must go down to keep the product constant.
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i dont really understand the question but
as what Mr Borek said 10^14 is a constant
water has 10^-7 [OH] and 10^-7 [H] aka pOH = 7, pH = 7, aka neutral solution.
while what determines the solution acidic or base isnt the total of pH and pOH aka 10^-14, its the concentration of OH and concentration of H not the total, we can look from [OH] perspective or [H] perspective .
if [OH] is high then its is base, based on Arrhenius Acid Base theory. if we look from [H] perspective, obviously when [OH] is high means [H] is low because [H] = 10^-14 / [OH] aka when [H] is low it is base.
cmiiw