Question

The pKas of chemicals HX and HY are 5 and 7 respectively. The pKa of cabonic acid H2CO3 is 6. If you make up an ether solution of chemicals HX and HY in a separatory funnel and then added an aqueous solution of NaHCO3, would both HX and HY stay in the ether? Or would either or both of them transfer into the aqueous layer? If one goes into the water layer, will it be in it's neutral (HX or HY) form or in its deprotonated anionic form?

Answer 1

Higher the pKa value greater will be the basicity. Lower the pKa value greater will be the acidity. Since HX has pKa value (5) lesser than the carbonic acid pKa (6), HX act as the acid in the reaction with carbonic acid.

If one makes an ether solution of HX and HY and then treated with a solution of NaHCO₃ in a separating funnel, HX move into the aqueous solution layer since it gets deprotonated by NaHCO₃ whereas HY remains in ether solution layer.

In water layer HX will be in its deprotonated anionic salt form.