Question

Why in some reaction water acts as strong base and in some weak.Base?

Answer 1

In contrast, only a fraction of the molecules of weak acids and weak bases react with water to produce ions, so weak acids and weak bases are also weak electrolytes. Typically less than 5% of a weak electrolyte dissociates into ions in solution, whereas more than 95% is present in undissociated form.

Answer 2

A strong base BOH dissociates completely in water, leaving only ions: BOH --> B+ + OH-. ... A weak base combines with water, reaching an equilibrium state in a reversible reactions: BOH + H2O <--> BH2+ + OH-. When the reaction is at equilibrium, all the products and reactants are present in some concentration.