[lrarava]

Hi I am new here.   But I cannot figure out the reason for cannot add indicator for neutralising acid and base when using titration experiment.   (Even though titration is not the best analysis method, but back titration) Can anyone please explain it?
Also, end point usually appears when indicator change colour, so if the experiment cannot use indicator for weak acid and weak base, is it still possible to find end point?

[mike]

Could you use a pH metre?

[cathy]

when you are doing titration without an indicator,
you can find the end point:
1. by change in pH value by using a pH meter
2. by change in temperature
3. by change in electrical conductivity
here are some example in my note...
http://hk.geocities.com/urabbit_hole/01.JPG
http://hk.geocities.com/urabbit_hole/02.JPG
Hope this can help you^^

[lrarava]

thank you for helping.

Beside what is the reason that cannot add indicator to weak acid and weak base titration?
Is it because it is hard to find an indicator at the range that weak acid and weak base become nutrual, but if so why indicator can be used for strong acid and strong base neturlisation?

[cathy]

actually, weak acid and weak will not have a centain result...
so we can't decide what indictor should be use...

http://hk.geocities.com/urabbit_hole/03.JPG

[lrarava]

thank you