A monoprotic weak acid, HA , dissociates in water according to the reaction HA ( aq ) − ⇀ ↽ − H + ( aq ) + A − ( aq ) The equili
brium concentrations of the reactants and products are [ HA ] = 0.170 M , [ H + ] = 2.00 × 10 − 4 M , and [ A − ] = 2.00 × 10 − 4 M . Calculate the value of p K a for the acid HA .
