The pKa of a weak acid is 5.85. The concentrations of the acid and its conjugate base are equal at a pH of

Question

The pKa of a weak acid is 5.85. The concentrations of the acid and its conjugate base are equal at a pH of (A) 6.85 (B) 5.85 (C) 4.85 (D) 7.85

Tardigrade Admin · Accepted Answer

Given, p Ka of a weak acid =5.85 Given, [salt] = [acid] According to Derson's-Hassel Balch equation, pH = p K a + log ([ text salt ]/[ text acid ]) pH =5.85+ log 1 pH =5.85

Q. The $p K_{a}$ of a weak acid is $5.85$ . The concentrations of the acid and its conjugate base are equal at a $p H$ of

6.85

5.85

4.85

7.85

Given, $p K_{a}$ of a weak acid $= 5.85$
Given, [salt] = [acid]
According to Derson's-Hassel Balch equation,
$p H = p K_{a} + lo g \frac{[ salt ]}{[ acid ]}$
$p H = 5.85 + lo g 1$
$p H = 5.85$

Q. The pKa​ of a weak acid is 5.85. The concentrations of the acid and its conjugate base are equal at a pH of