Titration Calculations?

Question

Calculate how much KHP is sufficient to react with approx 25mL or 0.10 mol L NaOH. Why?

Answer 1

Laura....the amount sufficient to react means that when the endpoint is reached ( like the phenolphthalein color change )...the endpoint is a good estimate of the true equivalence point. The equivalence point is where the amount of base = the amount of acid. At that point, meq of base added = meq of acid present.

So   meq = (Vol)(N) and also = wt of substance /meq weight

so  (Vol NaOH)( NNaOH) = wt KHPH/0.2042 grams/meq

( KHPH is monoprotic so its formula weigyt and equivalent weight are the same ..= 204.2 ,  1/1000 this figure is the me weight

so 25 mL ( 0.1N ) = wt /0.2042

wt of KHPH = 25 ( 0.1 ) ( 0.2042 ) =  0.5105 grams