Question

Which of the following is a proper buffer substituent pair?

Answer 1

Answer:

$\boxed{\text{c. Neither a nor b is correct}}$

Explanation:

A buffer pair consists of either

• A weak acid and its salt or
• A weak base and its salt

(a) Oxalic acid and sodium oxalate

$\rm H _2 C _2 O _4 + Li _2 C _2 O _4 \longrightarrow \, 2LiHC _2 O _4$

Oxalic acid is an acid and lithium acid is a base. Together, they will neutralise each other and form the salt LiHC₂O₄.

A solution of LiHC₂O₄ is not a buffer.

The correct buffer pair is H₂C₂O₄ and LiHC₂O₄

(b) Carbonic acid and sodium carbonate

$\rm H _2 CO _3 + Na _2 CO _3 \longrightarrow \, 2NaHCO _3$

The carbonic acid and the sodium carbonate will neutralise each other and form the salt NaHCO₃.

A solution of NaHCO₃ is not a buffer.

The correct buffer pair is H₂CO₃ and NaHCO₃

$\boxed{\textbf{Neither a nor b is correct}}$