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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: jokulsa on October 05, 2014, 11:01:51 AM

Title: pH of 0.56M HF (pKa = 3.14)
Post by: jokulsa on October 05, 2014, 11:01:51 AM

How do I find the pH of 0.56M of hydrofluoric acid HF?

(pKa = 3.14)

some working would be great
thanks

Title: Re: pH of 0.56M HF (pKa = 3.14)
Post by: sjb on October 05, 2014, 11:06:35 AM

Quote from: jokulsa on October 05, 2014, 11:01:51 AM

How do I find the pH of 0.56M of hydrofluoric acid HF?

(pKa = 3.14)

some working would be great
thanks

What is the definition of pKa?

Title: Re: pH of 0.56M HF (pKa = 3.14)
Post by: jokulsa on October 05, 2014, 11:10:02 AM

pKa is the negative log of the Ka value isn't it?

Title: Re: pH of 0.56M HF (pKa = 3.14)
Post by: Hunter2 on October 05, 2014, 11:13:33 AM

Yes and how is ka defined.

Title: Re: pH of 0.56M HF (pKa = 3.14)
Post by: jokulsa on October 05, 2014, 11:16:20 AM

Ka is the acid dissociation constant, tells you how strong an acid is

Title: Re: pH of 0.56M HF (pKa = 3.14)
Post by: sjb on October 05, 2014, 11:28:31 AM

Quote from: jokulsa on October 05, 2014, 11:16:20 AM

Ka is the acid dissociation constant, tells you how strong an acid is

How does it do that?

Title: Re: pH of 0.56M HF (pKa = 3.14)
Post by: jokulsa on October 05, 2014, 11:36:55 AM

I really don't know...  ???

Title: Re: pH of 0.56M HF (pKa = 3.14)
Post by: Hunter2 on October 05, 2014, 11:37:14 AM

https://www.khanacademy.org/science/chemistry/acids-and-bases/v/ph-of-a-weak-acid