Hi,

 

I was asked this question by my friend and when I gave away my answer he was unconvinced. So I ask you whether I was right or not.

 

He asked me what was the actual meaning of 'End-Point' when you do titration. I said that it is meant to be the end of reaction indicator. He argued that if that was the case then when we do neutralisation using a strong alkali and a weak acid then why the graph of that reaction shows that the end-point(in terms of ph) might have reached at ph9.

 

I was so confused about it that i told him that end-point does not necessarily means to reach a certain ph which might indicate us that the reaction has completed. I told him if he'd done a redox titration then ph was out of the question. But, still he looked unsatisfied.

 

All I ask is can any 1 tell me how to best define endpoint and when we do a titration of a strong alkali with a weak acid, maybe use a buffer as well then how can we find the endpoint in the graph for that reaction(titration).

 

Anyhelp will b appreciated

End point when the (moles of HI=moles of I minus) where I am talking about the indicator (I). The indicator has the property such that the conjugate acid is one colour and the conjugate base for the indicator is another. the blending of the two is what you are looking for so the endpoint of a titration is just that.

The pH could be anything. yes a strong acid and weak base and visa versa form a buffer but that isn't your endpoint.