The organic compound tris-hydroxymethyl aminomethane is abbreviated Tris and is basic. The conjugate acid (TrisH+ ) has a p  K a of 8.10.

TrisH ⁺  + H ₂ O ⇌ Tris + H ₃ O ⁺

Tris is commonly used as a component in buffer solutions to study biochemical reactions.

a) A buffer solution is prepared by mixing 12.0 mL of 0.100 molL−1HCl with 24 mL of 0.100 molL−1Tris. What is the pH of this buffer?

b) The buffer was used to study an enzyme-catalyzed reaction in which 0.00010 mol of H3O+ was produced. What is the pH of the solution after the acid reacted with the buffer?