Question

A buffer contains significant amounts of a weak acid and its conjugate base. The acid consumes any added base, and the base consumes any added acid. In this way, a buffer resists pH change. Part A Which set of compounds would form a buffer in aqueous solution?

NaF and NaOH

NaF and KF

HCN and NaCN

HF and KF

HCl and HClO

HBr and NaBr

HF and KCN

NaCl and KCl

Please say if they are a buffer or not a buffer

Answer 1

acidic buffer is formed by weak acid and salt of weak acid

basic buffer is formed by weak base and salt of weak base

NaF and NaOH:

NaOH and F- are both base.

So, this is not a buffer

NaF and KF

this has only F- which is base

So, this is not a buffer

HCN and NaCN

HCN is weak acid and CN- is its conjugate base

So, this is buffer.

HF and KF

HF is weak acid and F- is its conjugate base

So, this is buffer.

HCl and HClO

HCl and HClO are both acids.

So, this is not a buffer

HBr and NaBr

HBr is strong acid and Br- is its base.

This is not a buffer due to strong nature of acid.

So, this is not a buffer

HF and KCN

HF is weak acid but its conjugate base is not present.

So, this is not a buffer

NaCl and KCl

Both are salt.

So, this is not a buffer