In: Chemistry
The acid C6H5COOH dissociates according to the equation: C6H5COOH (aq) ⇌ C6H5COO‐ (aq) + H+ (aq) K = 6.4 x 10‐5 If the initial [C6H5CO2H] is 4.59 x 10‐3M, what are the equilibrium concentrations of C6H5COO‐ and H+ for this dislocation reaction?
C6H5COOH (aq) <-------> C6H5COO‐ (aq) + H+
(aq)
4.59*10^-3
M
0
0
4.59*10^-3
-X
X
X
K = [C6H5COO‐] [H+] /[C6H5COOH ]
6.4*10^-5 = X*X / (4.59*10^-3 -X)
2.94*10^-7 - 6.4*10^-5* X = X^2
X^2 + 6.4*10^-5* X - 2.94*10^-7 = 0
Solving above quadratic equation we get,
X = 5.1*10^-4 M and X = -5.8*10^-4 M
But X can't be negative since it is concentration of product
So,
X = 5.1*10^-4 M
So equilibrium concetration of C6H5COO‐ and H+ is X which is equal to 5.1*10^-4 M