[jess2009]

hi all,
i need to brush up my chem skills with regard to inflexion point & end points? whats the difference between teh two and how would you determine it on an acid-base titration curve? I am new to this forum and not good @ chem ofcourse, do you guyz recomment any good website or books that might be helpful?

pS. i was titrating sodium dihydrogen phosphate dibasic with 1.0 M NaOH and i am not sure how to determine 1st & 2nd inflexion point on the graph??

please help

[Borek]

Basically what you are looking for is a difference between end point and equivalence point.

http://www.titrations.info/titration-basic-terms

Browse the site, you may find many interesting things there.

Only one inflection point on the dihydrogen phosphate titration curve, so you will be not able to determine two of them:

http://www.titrations.info/acid-base-titration-phosphoric-acid

Remember that titration curve presented there is calculated for phosphoric acid. If you start with dihydrogen phosphate, you are already past first end point - and there is only one ahead.