Tetra Posted May 25, 2011 Share Posted May 25, 2011 We're currently on the Equilibrium unit, and I'm having problems with some questions. 1) Given a 0.015 M solution of HOCN with a pH of 2.4, find the ionization constant, Ka. I know that ka = ([H+] [OCN])/ [HOCN], and i can calculate for the concentration of H+ and HOCN. But how do we find the concentration of OCN>? 2) Given a 0.015M solution of an unknown base with pH10, find: a) The concentrations of hydroxide and hydronium ion b) Kb I think for part a) I use the -log[H+] = 10 to find the concentration of H+. But then what about hydroxide? And as for b), Kb = Kw / Ka, but since we don't know Ka, how do we solve for this? Sorry if it's a bit confusing, but I'm also confused. I really don't understand this unit. Link to comment Share on other sites More sharing options...
John Cuthber Posted May 25, 2011 Share Posted May 25, 2011 Do you know what Kw means? When you add OH- ions to water what happens to the H+ ions? Link to comment Share on other sites More sharing options...
Tetra Posted May 27, 2011 Author Share Posted May 27, 2011 Kw is the equilibrium constant of water...but I'm not sure what that means. As for adding OH, it would react with the H to form water molecules? Link to comment Share on other sites More sharing options...
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