A 0.288 g sample of an unknown monoprotic organic acid is dissolved in waterand titrated with a 0.115 M sodium hydroxide solution. After the addition of 17.54 inl. of base, a pH of 4.92 is recorded. The equivalence point is reached when a total of 33.83 mL of NaOH is added. (a) What is the molar mass of the organic acid? (b) What is the K_a value for the acid? The K_avalue could have been determined very easily if a pH measurement had been made after the addition of 16.92 mL of NaOH. Why?

A 0.288 g sample of an unknown monoprotic organic acid is dissolved in

1.	A 0.288 g sample of an unknown monoprotic organic acid is dissolved in waterand titrated with a 0.115 M sodium hydroxide solution. After the addition of 17.54 inl. of base, a pH of 4.92 is recorded. The equivalence point is reached when a total of 33.83 mL of NaOH is added. (a) What is the molar mass of the organic acid? (b) What is the K_a value for the acid? The K_avalue could have been determined very easily if a pH measurement had been made after the addition of 16.92 mL of NaOH. Why?
Answer» SOLUTION :`(a) 74, (b) 1.3 xx 10^(-5)`