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The most important concepts in Acid-Base chemistry is a first buffers are solutions that resist changes in the PH when either an acid or bases
added instead of adding large increases and decreases in the PH a bath firm maintains an almost but not exactly constant PH
buffers are made up of either weak acid with its kanji get base or a week base with its kanji get acid
so as an example
one leader of the solution that's made up of
ammonia
ammonia is a weak base and as a KB of 1.8 times 10 to the negative fifth
and in the same solution we have
ammonium chloride ammonium chloride
is a salt
and when you dissociate the salts you get the Monet and cat ion chloride an ion
chloride an ion is the kanji get of Ida Clark acid
therefore it is not an acid not a base its neutral
the Monet and cat ion is the kanji get of the week base ammonia
so we have a week base with its kanji get acid
this solution will
be a buffer
when you recognize a solution is a ba for there's a quick way to calculate the PH
which is called the Henderson also Bach formula
PH is equal to PKA of the acid
plus the log of the concentration of base divided by acid
PKA
is for the chemical that has a KA
and each four plus is our weak acid so we can calculate KA because it's not in the table KA is KW divided by KB
so the KA of the Monet and cat ion 5.56 times tend to the -10th
we can use that to calculate
PKA
which gives us a PKA of 9.25
so now on this edition also Bach formula
we want a find the PH of the ball for the PK A's 9.25
and then the important thing in this formula is payable two identify the acid in the base correctly
the acid molar the 0.5 and that goes in the dominator
the base molar the 0.4 goes in the numerator
so depending on what he have more acid or more base in your buffer
the PH will either increase and decrease from the PK value in this case
we have more acid
and add that is going to decrease our PH from our PKA the PH is
9.15
notice in this formula
if you made a buffer when the concentration of the base equals the concentration of the acid then this term
would be the log of won and the log of one is zero so under those conditions the PH of your buffer is just equal to the PKA