X mg of an unknown acid was titrated with 0.110 M sodium hydroxide. Calculate X by

Question

X mg of an unknown acid was titrated with 0.110 M sodium hydroxide. Calculate X by

subtracting the last two digits of you student ID in mg from 400 mg. The equivalence point is at

25.00 mL. What is the molar mass of the unknown acid?

Answer 1

Lets set X = 50 mg for the following work.

mass of unknown acid = 400 mg - 50 mg = 350 mg = 0.350 g

moles@equivalence = 25.00 mL *1L/1000mL * 0.110 M =0.00275moles

This is the number of moles of acid and base at equivalence!

Now:

moles @ equivalence = grams of acid / molecular weight of acid

0.00275 moles = 0.350 g / x

x = 0.350 g / 0.00275 moles

x = 127 g/mol

Enjoy!