Phosphorous acid, H 3 PO 3 ( aq ) , is a diprotic oxyacid that is an important compound in industry and agriculture. p K a1 p K a2 1.30 6.70 Calculate the pH for each of the points in the titration of 50.0 mL of 1.5 M H 3 PO 3 ( aq ) with 1.5 M KOH ( aq ) . A molecule of phosphorous acid. A central phosphorus atom is single bonded to a hydrogen atom and two O H groups. An oxygen atom is also double bonded to the phosphorus atom.

a. before addition of any KOH :

b. after addition of 25.0 mL KOH :

c. after addition of 50.0 mL KOH :

d. after addition of 75.0 mL KOH :

e. after addition of 100.0 mL KOH :