I done part a and got 2.73 but I'm not sure how to do part b
Sodium ethanoate contains CH3COO^- ions, which are the conjugate base of ethanoic acid, CH3COOH.
What has happened is you have formed a buffer solution containing 0.1 mol of CH3COO^- ions and 0.2 mol of CH3COOH and so now it is no longer true that [CH3COO^-] = [H^+].
Let [H^+] = x. Use the Ka expression again and solve for x. After finding x, what might be the logical thing to do with it?
Sodium ethanoate contains CH3COO^- ions, which are the conjugate base of ethanoic acid, CH3COOH.
What has happened is you have formed a buffer solution containing 0.1 mol of CH3COO^- ions and 0.2 mol of CH3COOH and so now it is no longer true that [CH3COO^-] = [H^+].
Let [H^+] = x. Use the Ka expression again and solve for x. After finding x, what might be the logical thing to do with it?
use -log[H^+]
so im just rearranging the Ka= [H^+][A^-]/[HA] right?
also when using the formula it doesn't matter that I don't have the volume because it cancels out right?
Perfect. It’s great to see you mastered the method so quickly and were able to spot that the volumes cancel in the Ka expression so there is no need to actually find the concentrations