Question

calculate the the pH of a 3.0M HF solution (assume 10% dissociation)

Answer 1

if the solution is 0.3M HF, and 10% of it dissociates, what's the concentration of the H+ and F- ions?\[HF(aq) \rightleftharpoons H^{+1}(aq) + F^{-1}(aq)\]

Answer 2

I'm not actually sure. Would they split evenly? Something like H= 1.5 and F=1.5?

As you can tell, I'm pretty lost right now.

Answer 3

the concentrations will be equal, but not that large. When an acid dissociates, it breaks apart into the 2 ions. If you start with 0.3M acid, and 10% of it dissociates, you'll have 0.27M acid "left over" that hasn't split up, and 0.03M H+ ions, and 0.03M F- ions.

Answer 4

sorry, 3M, not 0.3M

Answer 5

It's okay. Okay, so I would end up with .3M H+ and .3M F- right?

Answer 6

So then how do I calculate the actual pH?

Answer 7

pH = -log(H+), which you just found. so take the -log(0.3)

Answer 8

okay. So 0.5338...?

Answer 9

It seems a bit low.

Answer 10

or would I subtract it from 14?