00:01
So we're given the acid dissociation constant for acetic acid and acetic acid is a weak acid and when it ionizes this is what we would have.
00:14
This water you're going to get the conjugate base, the acetate ion and hydronium ion.
00:22
Right so we're told that we have a 2 .6 molar acetic acid solution right but calculate the ph.
00:32
Now here's it right the we're going to have the ice table initially we had this to be 2 .6 not this we don't know any of this neither do we know any of that.
00:44
To change some of this would have been lost right uh sorry this is not important and this would have been gained and that would have been gained.
00:54
At equilibrium you would have 2 .6 minus x this will be x and that will be x.
01:01
Now the acid dissociation constant the ka would be the concentration of the conjugate base and hydronium ion at equilibrium divided by the concentration of the acid itself and if you work that out you have the values there.
01:20
Now here's it because the value the ka value of the acid is 1 .8 times 10 to the power of minus 5 because of this small value right of the the acid dissociation constant the value of this at equilibrium will be approximately 2 .6 right the minus x would cancel.
01:42
Just take note that usually once this is less than is greater or sorry is less than minus 3 right if this value is less than minus 3 you can always ignore it right it's it's safe to say usually you can always ignore it...