Question

Write balanced net ionic equations showing how the lactate buffer, acts to oppose a change in pH upon addition of acid (H+) and upon addition of base (OH-)

Answer 1

LActic acid --> CH3CH(OH)COOH

A buffer is any type of substance that will resist pH change when H+ or OH- is added.

This is typically achieved with equilibrium equations. Both type of buffer will resist both type of additions.

When a weak acid and its conjugate base are added, they will form a buffer

The equations:

The Weak acid equilibrium:

CH3CH(OH)COOH(aq) <-> H+(aq) + CH3CH(OH)COO-(aq)

Weak acid = CH3CH(OH)COOH(aq)

Conjugate base = CH3CH(OH)COO-(aq)

Neutralization of H+ ions:

CH3CH(OH)COO-(aq) + H+(aq) <-> CH3CH(OH)COOH(aq); in this case, HA is formed, H+ is neutralized as well as A-, the conjugate

Neutralization of OH- ions:

CH3CH(OH)COOH(aq) + OH-(aq) <-> H2O(l) + CH3CH(OH)COO-(aq) ; in this case; CH3CH(OH)COO- is formed, OH- is neutralized as well as CH3CH(OH)COOH.