Illustrate how a buffer works using the C2H5NH2/C2H5NH3+ buffer system. Show with equations how base/conjugate acid system affects bases/acids

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jerichorayel | College Teacher | (Level 2) Senior Educator

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A buffer solution is an aqueous solution that contains a weak acid and its conjugate base and weak base and its conjugate acid. Ethylamine (C2H5NH2) is a weak base with pKb = 3.3 and its conjugate acid is the protonated version which is the C2H5NH3+. It can be seen in the following equilibrium equation:

`C_2H_5NH_2 + H_2O <=> C_2H_5NH_3 ^+ + OH^(-)`

In order to get the acidity (pH or POH) of the ethyl amine solution, we can use the simplified expression called the Henderson-Hasselbalch equation:

`pOH = pK_b + log [((BH^(+)))/((B))]`


`pOH = pK_b + log [((C_2H_5NH_3 ^+))/((C_2H_5NH_2))]`