Question

Buffers are solutions that resist changes in pH. find a "common" buffer system and explain what the buffering components are.

post should be a minimum of 150 words

No hand writing please

Answer 1

Buffer solution usually consist of -

1) a mixture of weak acid and its salt(acetic acid and sodium acetate)

2) a mixture of weak base and its salt(ammonium hydroxide and ammonium chloride)

Let us explain how a buffer solution acts and maintains pH constant. In an acidic buffer like acetic acid and Sodium acetate, ionisation of weak acid is suppressed by the salt and the solution contains a large amount of unionized acetic acid ,a large amount of Acetate ions and a small amount of H₃O⁺ ions. if a strong acid(HCl) is added to such a mixture the equilibrium is disturbed ; H₃O⁺ Ions added would combine with the Acetate Ions forming unionized Acetic Acid according to the neutralization reaction .

H₃O⁺ + CH₃COO^- = CH₃COOH + H₂O

Thus Acetate ions of the mixture neutralize the added acid and thereby pH of the buffer solution is almost maintained constant.

However, addition of hydroxyl ions in the form of strong base(NaOH) neutralizes the acid ,forming salt and water .

OH^- + CH₃COOH = CH₃COO^- + H₂O

The pH of the solution remains very close to its original value.