Buffers

[Rohita Thammineni 2D]

Hi! Can someone explain how we can determine whether a buffer is acidic or basic? I'm kind of confused about where salts get involved in this and how buffers work in general honestly...

[Sophia Zhao]

Buffers are solutions created using a weak acid and a salt containing its strong conjugate base, or using a weak base with a salt containing its strong conjugate acid. If it's the former, it's an acidic buffer, and if its the latter it's a basic buffer.

[Jake 1F]

The goal of a buffer is to maintain pH at a certain level. To do this you need to have both proton donors and acceptors present in similar amounts so that it can respond to increases H or OH. This is where the salts come in. To make a buffer, you first need some weak acid/base solution, but there is not enough of its conjugate base/acid yet to work as both a donor AND a sink. So, you need to increase the concentration of the conjugate by adding it it in the form of a salt. The other part of the salt has to be the conjugate acid/base of a strong acid/base so it has no influence on the equilibrium and you're left with similar amounts of a weak acid-base pair.

[Hailey Sarmiento 3E]

a buffer has equal amounts of acid and conjugate base or base and conjugate acid in order to neutralize all acids and bases in the mixture.

[jaycmartinezDisc3b]

This will honestly come down to looking at the equation and determining if the reactants are acidic or basic. Buffers are made using the conjugate of whatever the reactant is in order to try to neutralize ph change. Hope this helps!

[Katherine Li 1A]

A buffer can be acidic or basic. The point of it is that if an acid is added to a basic buffer or vice versa, the buffer's pH doesn't change very much.

[Sasha Gladkikh 2A]

Hi,

Buffer solutions resist a change in pH when small amounts of a strong acid or a strong base are added.

Acidic Buffer:
• These solutions consist of a weak acid and a salt of its conjugate base. Note: The cation of the salt has to be a spectator ion (i.e., derived from a strong base).
• An example of a buffer that consists of a weak acid and its salt is a solution of acetic acid (CH₃COOH) and sodium acetate (CH₃COONa).

Basic Buffer:
• These solutions consist of a weak base and a salt of its conjugate acid. Note: The anion of the salt has to be a spectator ion (i.e., derived from a strong acid).
• An example of a buffer that consists of a weak base and its salt is a solution of ammonia (NH_3(aq)) and ammonium chloride (NH₄Cl_(aq)).