Henderson-Hasselbalch equation

noun

Hen·​der·​son-Has·​sel·​balch equation ˈhen-dər-sən-ˈhas-əl-ˌbälk- 

: an equation that equates the pH of a buffered solution (as the blood) to the sum of the cologarithm (p) of the dissociation constant (K) of the acid in the buffer and the logarithm of the ratio of the concentration ([ ]) of the salt to that of the acid and that is written