Answer to Question #154725 in Physical Chemistry for Fred

Question

Using some of the following reagents, describe the preparation of 500 mL, pH 7 citric acid

1.8 M citric acid (H₃C₆H₅O₇, FW = 192)

1.2 M sodium dihydrogen citrate (NaH₂C₆H₅O₇, FW = 214)

1.5 M sodium hydrogen citrate (Na₂HC₆H₅O₇, FW = 236)

0.8 M sodium citrate (Na₃C₆H₅O₇, FW = 258)

0.1 M HCl

0.1 M NaOH

distilled water

For citric acid, Ka₁ = 7.4 x 10^-4, Ka₂ = 1.7 x 10^-5, Ka₃ = 4.0 x 10^-7

Answer 1

1. 250ml 1.8 M citric acid + 92ml 0.1 M NaOH + 158ml distilled water
2. 250ml 1.8 M citric acid + 11ml 0.1 M NaOH + 239ml distilled water
3. 250ml 1.8 M citric acid + 2ml 0.1 M NaOH + 248ml distilled water
4. 250ml 0.1 M HCl + 32ml 0.8 M sodium citrate + 218ml distilled water