Question

# (a) Calculate the solubilit y of calcium oxalate (CaC2O4) in 1.0 M oxalic acid (H2C2O4) at 25°C, using the two acid ionization constants for oxalic acid and the solubility product Ksp = 2.6×10^-9 for CaC2O4. (b) Calculate the solubility of calcium oxalate in pure water at 25°C. (c) Account for the difference between the results of (a) and (b).

Solution

Verified
Step 1
1 of 6

$\textbf{a)}$Assume that $x$ M of CaC$_2$O$_4$ dissolves at equilibrium. The concentration of Ca$^{2+}$ denote by $x$ and C$_2$O$_4^{2-}$ reacts with H$_2$C$_2$O$_4$:

$\text{C_2O_4^{2-}} + \text{H_2C_2O_4} \rightleftharpoons 2 \text{HC_2CO_4^-}$

The $K$ is:

$K=\dfrac{[\text{HC_2CO_4^-}]^2}{[\text{H_2C_2O_4} ][\text{C_2O_4^{2-}}]}=\dfrac{K_{a_1}}{K_{a_2}}$

$K=\dfrac{6.5 \cdot 10^{-2}}{6.1 \cdot 10^{-5}}=1065$

## Recommended textbook solutions #### Pearson Chemistry

ISBN: 9780132525763 (1 more)Matta, Staley, Waterman, Wilbraham
3,748 solutions #### Chemistry: The Central Science

14th EditionISBN: 9780134414232 (5 more)Bruce Edward Bursten, Catherine J. Murphy, H. Eugene Lemay, Matthew E. Stoltzfus, Patrick Woodward, Theodore E. Brown
7,741 solutions #### Modern Chemistry

1st EditionISBN: 9780547586632Jerry L. Sarquis, Mickey Sarquis
2,184 solutions #### Principles of Modern Chemistry

8th EditionISBN: 9781305079113 (3 more)David W. Oxtoby, H. Pat Gillis, Laurie J. Butler
1,527 solutions