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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: 2clients on March 17, 2009, 05:21:48 PM

Title: calculating pH and hydronium ion concentration.
Post by: 2clients on March 17, 2009, 05:21:48 PM

Hello there,

I'm a little lost on this one:

Calculate the hydronium ion concentration and pH in a 0.5 M solution of NH4Cl.

I know pH = -log[H+], but I'm unsure how to find [H+].  Probably I need a Ka value for NH4Cl?

Any help is greatly appreciated!

David

Title: Re: calculating pH and hydronium ion concentration.
Post by: 2clients on March 17, 2009, 05:29:44 PM

So after thinking about it more, I think an ICE table is appropriate here, and I could set (x^2)/(.5-x) = Ka of NH4Cl.

Solving for x will give [H+] and then I could take the negative log to get pH? I'm not finding the Ka value online...

Title: Re: calculating pH and hydronium ion concentration.
Post by: Borek on March 17, 2009, 06:13:40 PM

NH₄⁺ is a conjugate acid of a weak base.