Question

Indicate the ionic species that predominates at ph 4, 8, and 11 for (a) ammonia and (b) phosphoric acid.

Answer 1

In case of ammonium phosphate ,

NH4+ will be at pH 4 & 8 due to acidic condition and phosphate at pH 11 due to basic condition.  

For Phosphoric acid :

At pH 4 , 8 and 11 :

H2PO4- .

HPO42- .

HPO42-  .

For ammonia :

At pH 4 , 8 and 11 :

NH4+

NH4+

NH3