Answer to Question #122797 in Organic Chemistry for Nyarko Benjamin

Question

Student X titrated 25.0cm3 of 0.1M K2CO3 with 0.1M HCl , using methyl Orange as indicator . Student Y carried out the same exercise but used Phenolphthalein as indicator. Which of the following statements about the Titrations is true?
A. The titre values obtained from the two titrations are equal.
B. The titre value for the titration by X is twice that by Y
C. The titre value for the titration by X is half that by Y
D.CO2(g) was released in there actions in both titrations

Answer 1

Correct answer is:

B. The titre value for the titration by X is twice that by Y.

methyl orange has colour transition at pH 3-4, acidic media, in which CO2 exists, the titration equation is

CO32- + 2 H+ = H2O + CO2.

phenolphtalein has transition at pH 7-8, neutral medium, in which HCO3- exists, the titration equation is

CO32- + H+ = HCO3-