A buffer solution of 0.080 M and 0.020 M is prepared

CHEMISTRY · Subjective · A Level · Chemistry · Acids and bases · Acids and bases

Problem

A buffer solution of 0.080 M

\text{Na}_2\text{HPO}_4

and 0.020 M

\text{Na}_3\text{PO}_4

is prepared. The electrolytic oxidation of 1.0 m mole RNHOH is carried out in 100 mL buffer to give.

\text{RNHOH} + \text{H}_2\text{O} \longrightarrow \text{RNO}_2 + 4\text{H}^+ + 4e^-

Calculate approximate pH of the solution after oxidation is complete.

pK_{a1}

pK_{a2}

and

pK_{a3}

\text{H}_3\text{PO}_4

are 2.12, 7.20 and 12.0 respectively.