The pH of ammonium phosphate solution, if `pK_(a)` of phosphoric acid and `pK_(b)` of ammonium hydroxide are 5.23 and 4.75 respectively, is _______.

Answer

7

Explanation

Since `(NH_(4))_(3)PO_(4)` is salt of weak acid `(H_(3)PO_(4))` and weak base `(NH_(4)OH)`.
`pH=7+(1)/(2)(pK_(a)-pK_(b))`
`=7+(1)/(2)(5.23-4.75)=7.24~~7`