JEE MainChemistryEasyPhysical Chemistry

pH of 0.1 M Na_2HPO_4 and 0.2 M NaH_2PO_4 are respectively:
(pK_a for H_3PO_4 are 2.2, 7.2 and 12)

Show answer and solution

For Na_2HPO_4, pH =

\frac{{pK}_{a_{2}} + {pK}_{a_{3}}}{2} = \frac{7.28 + 12}{2} = 9.6

.
For Na_2HPO_4, pH =

pH = \frac{{pK}_{a_{1}} + {pK}_{a_{2}}}{2} = \frac{2.2 + 7.2}{2} = 4.7

Source: Grass-G / CH-24 Chemistry Paper 31 Dec..docx

Need a video for this idea?

Scan any doubt from your notes and get a whiteboard explanation.