What is the significance of the equivalence point in acid and base titrations?

[Scharles]

http://img19.imageshack.us/img19/2692/chptitration.jpg

http://img130.imageshack.us/img130/6351/titrationfigure1.jpg

1.)For the titration of strong acid and strong base, and at the beginning of the curve, how to explain the big amount of base added only increase a little of the pH value since it was not a buffer region.

2.)The line of point S or equivalence point is a straight line or steep/slope to left hand side ??

thanks~~

 

[Umbra Lupis]

The equivalence point occurs ideally when at an inflection point. That is when slope reaches a extremum (want $$\frac{d^2(pH)}{dV^2} = 0$$) - however I have found that rarely happens in real life - you want the point closest to where this is true.

I am still thinking about the first part.