In a titration of 34.0 mL of a 0.425 M solution of a diprotic acid H₂C₄H₄O₆ (tartaric acid) with 0.155 M LiOH, how many mL of base are required to reach the first equivalence point?

Question

please be accurate in rounding

Answer 1

The balanced equation to reach the first equivalence point is

H2C4H4O6 + LiOH → HC4H4O6Li + H2O.

This is a 1:1 mole ratio of tartaric acid to LiOH, so the number of moles of LiOH added must be equal to the number of moles of tartaric present in solution.

Molecular mass of tartaric acid = 150.0 g, so the number of moles of tartaric acid present is 0.425 m/L x 1L/1000 mL x 34.0 mL = 0.01445 moles.

Therefore, 0.01445 moles of LiOH must be added to reach the first equivalence point.

Since the molarity of LiOH titrant is 0.155 M, we can write 1000 mL/L x 1/0.155 m/L  x 0.01445 moles = 93.2 mL LiOH.

Check my math.