In a experiment to determine the molecular weight and the Ka for ascorbic acid (vit. c.) a student dissolved 1.3713g of the monoprotic acid in water to make 50 mL of solution. The pH was monitored throughout the titration. The equivalence point was reached when 35.23 mL of the base was added.

1) Calculate the molecular mass of ascorbic acid.

2) When 20mL of NaOH was added during the titration the pH was 4.23. Calculate the Ka for ascorbic acid.

3) What was the pH at the equivalence point?

To find molecular mass of an acid in a titration experiment, one must use this formula:

Ca*Va=Cb*Vb
therefore
Ca=(Cb*Vb)/Va

C=concentration (molarity)
V=volume
a=acid
b=base

Thanks for the answer, but I haven't yet seen that formula yet, can you tell me the name for the formula?

The formula you are referring to is called the dilution formula or the concentration-volume formula. It is commonly used to calculate the concentration of a solution after dilution or mixing.

In this particular case, the formula is used to find the concentration of ascorbic acid (Ca) based on the concentration of the base (Cb), volume of the base (Vb), and volume of the acid (Va). By rearranging the formula, you can solve for Ca:

Ca = (Cb * Vb) / Va

This formula is derived from the concept of stoichiometry and the principle of conservation of mass in a chemical reaction.

The formula you are referring to is called the acid-base titration formula or the neutralization formula. It is commonly used in titration experiments to calculate the concentration or volume of a solution.