Study the following table. [table] Buffer solution | Volume (in mL) of 1 M weak acid | Volume (in mL) of 0.1 M sodium salt of weak acid ; I | 4.0 | 4.0 ; II | 4.0 | 40.0 ; III | 40.0 | 4.0 ; IV | 0.1 | 10.0 [/table] Which of the two sets of buffer solutions have least pH?

Question

Dr. Abubacker · Accepted Answer

(b)
For a buffer solution, pH is given by Henderson equation.
$pH = pK_{a} + \log\frac{\lbrack salt\rbrack}{\lbrack acid\rbrack}$
hence, $pH\$is least when concentration of acid is higher than that of salt.

Q. Study the following table. [table] Buffer solution | Volume (in mL) of 1 M weak acid | Volume (in mL) of 0.1 M sodium salt of weak acid ; I | 4.0 | 4.0 ; II | 4.0 | 40.0 ; III | 40.0 | 4.0 ; IV | 0.1 | 10.0 [/table] Which of the two sets of buffer solutions have least pH?

Explanation

Reviewed by Dr. Abubacker

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