Question

Phthalic acid (H,C,H,O,) is a diprotic acid with K 1 = 1.12 x 10- and K 2 = 3.90 x 10-Determine the pH of a 0.177 M phthalic acid (H,C,H,O,) solution. pH = about us Career P o licy Terms of use contacts 12.50

Answer 1

For aqueous solution of weak acids , the first dissociation is only taken care of . The 2nd dissociation does not happen . Now , for weak acid , the equation of pH is ,

$pH=-log(k_{a}\times C)^{0.5}$

here k_a1 is taken . C is concentration of acid .

$\therefore pH=-log(1.12\times 10^{-3}\times 0.177)^{0.5}$

$\therefore pH=1.85$

[ANSWER]