A solution of NaOH was standardized by gravimetric titration of a known quantity of the primary standard, potassium hydrogen phthalate:

Potassium hydrogen phthalate C₈H₅O₄K, FM 204.22

The NaOH was then used to find the concentration of an unknown solution of H₂SO₄:

H₂SO₄ + 2NaOH→Na₂SO₄ + 2H₂O

(a) Verify from the structure of potassium hydrogen phthalate that its formula is C₈H₅O₄K.

(b) Titration of 0.824 g of potassium hydrogen phthalate required 38.314 g of NaOH solution to reach the end point detected by phenolphthalein indicator. Find the concentration of NaOH (mol NaOH/kg solution).

(c) A 10.00-mL aliquot of H₂SO₄ solution required 57.911 g of NaOH solution to reach the phenolphthalein end point. Find the molarity of H₂SO₄.

Transcribed Image Text:

CO,H CO,Na + NAOH + H,0 CO,K CO,K