I\'ve been able to get the first half of the problem correct but the second half
ID: 870857 • Letter: I
Question
I've been able to get the first half of the problem correct but the second half Im having issues with.
Help would be much appreciated!! Thank you!
The flask shown here contains 0.856 g of acid and a few drops of phenolphthalein indicator dissolved in water. The buret contains 0.320 M NaOH. What volume of base is needed to reach the end point of the titration? What is the molar mass of the add (assuming it is diprotic and that the end point corresponds to the second equivalence point)? Add base to the solution until it just turns pink. You may need to reset the titration if you go past the end point.Explanation / Answer
NaOH molarity = 0.320 M
NaOH volume = 22 ml
no of moles of base = molarity x volume(ml)/1000
= 0.320 x 22/1000
= 7.04 x 10^-3
no of moles of acid = weight/molar mass
= 0.856/molar mass
reaction H2A + 2NaOH -----------------------> Na2A + 2H2O
at end point number of moles of acid = number of moles of base
acid moles = 1/2 (base moles )
0.856/molar mass = 1/2 (7.04 x 10^-3)
molar mass = 243.18g/mol