Question

when weak base and strong acid are mixed then what happened​

Answer 1

Answer:

when a strong acid reacts with a strong base,when H3O+ and OH- are present in equivalent amount then salt and water is formed,solution becomes neutral and 57 kj per mole energy is evolved.

Eg: NaOH +HCl=NaCl+H2O

Answer 2

When Weak base reacts with strong acid

For eg :- NH3 + HCl ———> NH4Cl

The NH4Cl ionises to form NH4+ and Cl-

The cation formed (NH4+) undergo hydrolysis as follows.

NH4+ + H2O ——> NH4OH + H+

Being weak base NH4OH is partially ionises and the solution contain greater concentration of H+ ions. Hence the solution becomes ACIDIC.

The solution becomes ACIDIC due to CATION HYDROLYSIS and hence the pH is less than 7.