Ka and Kb

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805329408
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Joined: Wed Nov 20, 2019 12:21 am

Ka and Kb

Postby 805329408 » Sat Jan 18, 2020 11:25 pm

When do we know when to use Ka and Kb when given a reaction equation?

Adam Kramer 1A
Posts: 103
Joined: Sat Aug 24, 2019 12:15 am

Re: Ka and Kb

Postby Adam Kramer 1A » Sat Jan 18, 2020 11:35 pm

If the problem is asking about pH, then you will most likely know you are dealing with Ka or Kb. If the solution is a base, you will most likely be dealing with Kb to find the concentration of OH-, but if it is an acid, you will most likely use Ka to find the concentration of H+ ions. Furthermore, you can use either to find the other by using the formula Ka*Kb=Kw.

Alexandra Bartolome 2H
Posts: 102
Joined: Sat Jul 20, 2019 12:17 am

Re: Ka and Kb

Postby Alexandra Bartolome 2H » Sun Jan 19, 2020 12:19 am

Ka uses the concentration of hydronium ions, so you would usually use it when dealing with acids. Kb uses the concentration of hydroxide ions, so you would usually use it when dealing with bases.

Norman Dis4C
Posts: 101
Joined: Sat Sep 28, 2019 12:16 am

Re: Ka and Kb

Postby Norman Dis4C » Sun Jan 19, 2020 10:40 am

You could use these two interchangeably since Ka * Kb = Kw, it's just a matter of conversion and what you're looking for.


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