pKa vs. Ka
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pKa vs. Ka
Hi! I'm a little confused on the difference in pKa and Ka values, and what they tell us about the acidity of something. I know they refer to the equilibrium constant, but I'm having some trouble connecting it all. Any help would be great, thanks!
Re: pKa vs. Ka
Ka would be the value before it goes through a log base 10. As the meaning p like in pH or pOH would have the [H] or [OH] values go through the logarithm and thus it would be the same for pKa.
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Re: pKa vs. Ka
pKa=-logKa, just like how pH= -log[H+]. When there is a larger Ka, there is a weaker acid.
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Re: pKa vs. Ka
Conceptually speaking, pKa is another way of representing Ka. They both show how strong an acid is (strong meaning how easily an acid will give up its hydrogen ion in an aqueous solution).
pKa is simply the -log(Ka), as previous students have written. Yet by taking the -log of the Ka value, pKa is usually an "easier" way to view Ka. For instance, if the Ka of an acid dissociation reaction is 1.0 * 10^-4, then the pKa would be 4. It is much easier to just say that the pKa is 4 than to say that the Ka is 1.0 * 10^-4.
The relationship between pKa, Ka, and acidity is this:
- smaller pKa --> larger Ka --> stronger acid
This is because pKa = -log(Ka), which can also be written as Ka = 10^-pka, so the smaller the pKa, the larger the Ka. And the larger the Ka, the stronger the acid since it is more likely to dissociate and produce H3O+ ions (which would result in more products than reactants in an acid dissociation reaction, hence the higher Ka value).
pKa is simply the -log(Ka), as previous students have written. Yet by taking the -log of the Ka value, pKa is usually an "easier" way to view Ka. For instance, if the Ka of an acid dissociation reaction is 1.0 * 10^-4, then the pKa would be 4. It is much easier to just say that the pKa is 4 than to say that the Ka is 1.0 * 10^-4.
The relationship between pKa, Ka, and acidity is this:
- smaller pKa --> larger Ka --> stronger acid
This is because pKa = -log(Ka), which can also be written as Ka = 10^-pka, so the smaller the pKa, the larger the Ka. And the larger the Ka, the stronger the acid since it is more likely to dissociate and produce H3O+ ions (which would result in more products than reactants in an acid dissociation reaction, hence the higher Ka value).
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Re: pKa vs. Ka
pka is the negative log of the ka and is simply a mathematical convention used to make the numbers easier to work with. Small ka means stronger (weak) acid. Big Ka means stronger (weak) acid because ka is the actual value of the equilibrium with no conventional manipulation being done.
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Re: pKa vs. Ka
The pKa is the pH value at which a chemical species will accept or donate a proton.
The lower the pKa, the stronger the acid and the greater the ability to donate a proton in aqueous solution.
The lower the pKa, the stronger the acid and the greater the ability to donate a proton in aqueous solution.
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Re: pKa vs. Ka
pKa and Ka are essentially the same thing and measure how strong an acid is. pKa= -log[Ka] similar to how pH= -log[H3O+]
Re: pKa vs. Ka
It's important to note what a lot of other people have already noted, pKa and Ka have an inverse relationship, so if an acid has a high Ka value, it will have a low pKa value. So, lets say you're given a list of pKa values and are asked to rank them in order of acidity, you would rank (from lowest to highest acidity) in order from highest pKa value to lowest pKa value.
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Re: pKa vs. Ka
Hi! The smaller the pKa value, the stronger the acid. The larger the Ka value, the weaker the acid. Hope this helps!
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Re: pKa vs. Ka
Hi! The larger the Ka value, the smaller the pKa value. Therefore, the smaller the pKa value, the stronger the acidity. Hope that helps!
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Re: pKa vs. Ka
pKa is similar to pH in that pKa = -log(Ka). When the Ka value is high the acid is stronger. This also means that the higher the Ka the lower the pKa. When the pKa value is low the acid is stronger.
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Re: pKa vs. Ka
pKa is -log[Ka] while Ka is 10^(-pKa). The larger the pka, the smaller the Ka meaning the stronger the acid is. While the smaller the pka, the larger the Ka, meaning the weaker the acid is.
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