[deutdeut]

What is the meaning of the equivalence point between the titration of ammonia and sulphuric acid?

[Yggdrasil]

In any titration, the equivalence point is when the acid/base that you are titrating is completely neutralized.  In terms of the titration curve, you can recognize the equivalence point because it is an inflection point of the graph.  This means that the derivative of the titration curve will reach a maximum/minimum (depending on whether you are titrating with acid or base) at the equivalence point.