00:01
A buffer is a solution that is formed from the combination of a weak acid or a weak base together with its salt.
00:13
We have here a buffer solution that is formed from combining 0 .3 molar of hf with 0 .2 molar of naf.
00:31
The volume of the buffered solution is one liter.
00:34
Now into this solution, we add 15 ml of 1 molar hcl.
00:44
We want to find the ph of the resulting solution.
00:49
So first, we take note that when acid is added to the buffer, it will react with the base component of the buffer so that the reaction is between the chloride ion, which is the conjugate base of the weak acid hf, hydrochloric acid to form hf.
01:16
So this is the net ionic equation involved.
01:20
Let's find first the initial moles.
01:26
So for f-, we have the molarity, which is 0 .2 times the volume, which is 1.
01:31
So that's also, that's going to be 0 .2.
01:34
For hf, we have 0 .3.
01:38
It's molarity times volume, which is 1.
01:40
So that's 0 .3.
01:42
And for the hcl, we have the molarity of 1 molar and the volume, it's 15 ml.
01:51
So we convert this into liters...