how do you know which ion is going to accept/give the proton

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Michelle Kang 2K
Posts: 9
Joined: Fri Sep 26, 2014 2:02 pm

how do you know which ion is going to accept/give the proton

Postby Michelle Kang 2K » Fri Dec 12, 2014 7:35 pm

Find the initial concentration of a weak acid or base in a solution of hydrazine, NH2NH2, with pH=10.20.
When writing the equation for this, how would you know if the hydrazine is going to give the proton to the water or if it is going to accept a proton from the water? Would you just have to memorize that hydrazine is a base or acid?

HelenMach 1J
Posts: 12
Joined: Fri Sep 26, 2014 2:02 pm

Re: how do you know which ion is going to accept/give the pr

Postby HelenMach 1J » Fri Dec 12, 2014 8:53 pm

It is an ampholytic compound, both a base Kb = 1.3 x 10−6 AND an acid: Ka = 8 x 10−9... so I am going to assume you're going to have to use your best guess...

Michelle Kang 2K
Posts: 9
Joined: Fri Sep 26, 2014 2:02 pm

Re: how do you know which ion is going to accept/give the pr

Postby Michelle Kang 2K » Sat Dec 13, 2014 12:05 am

Oh I think I got it. Is it because of the pH the question gives? Since it has a pH of 10.2, then it would be more basic. ?

saialam 1A
Posts: 13
Joined: Fri Sep 26, 2014 2:02 pm

Re: how do you know which ion is going to accept/give the pr

Postby saialam 1A » Sat Dec 13, 2014 3:11 pm

Yea usually they give you the Ka or Kb, and whatever they give you usually tells you whether the compund is an acid or a base. If not then the pH should tell you, or the compund will be really obvious like Acetic Acid.


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